Traxxas Revo 5310 Owner's Manual

MODEL 5310

owner

’

s manual

Before You

3

Proceed

Safety

4

Precautions

Tools, Supplies

5

and Required
Equipment

Anatomy of Your

6

Revo

Quick Start:

7

Getting Up to
Speed

Gluing the Tires

8

and Decorating
Your Revo

The Traxxas

9

TQ-3 Radio
System

The TRX 2.5R

18

Racing Engine

Driving

33

Your Revo

Basic Tuning

34

Adjustments

Maintaining

40

and Storing
Your Revo

Advanced Tuning

42

Adjustments

Index

46

Introduction

Thank you for purchasing the Traxxas Revo. We believe you have
chosen the finest, most technologically advanced R/C monster truck
available. Revo proudly represents Traxxas’ passionate commitment
to innovation, ultimate performance, and unmatched engineering.
Revo demonstrates true state-of-the art engineering in its radically
advanced suspension, chassis, and transmission design. This new
model takes Traxxas’ “drive anywhere, over anything” mandate to a
higher level of performance authority. There is simply no other R/C
product like it.

Like an F-1 racing car, Revo is equipped with an extremely powerful,
efficient, lightweight, engine; the TRX 2.5R Racing Engine. The power
and reliability of the TRX 2.5R Racing Engine has been proven in
thousands of Traxxas models. The rear exhaust design, trick porting,
and sophisticated carburetor all come together for dramatic, high­revving power output. Add to that the smooth convenience of the
on-board EZ-Start electric starting system and the TRX 2.5R Racing
Engine remains in a class all by itself. Revo has been carefully
engineered to keep its weight low and maintain an incredible power­to-weight ratio and seemingly perfect performance balance. You can
expect quick acceleration to speeds in excess of 40mph (64.37 kph).

With all of this high-end technology jammed between the wheels of
your new Revo, it’s very important that you take some time to read
through these instructions. This manual contains all the necessary
set-up, break-in, tuning, and operating procedures that allow you to
unlock the incredible performance and adjustment potential built
into Revo.

important to read and follow the procedures in this manual. Revo
contains new technologies in the engine, suspension, and
transmission operation that you may not be familiar with. Pay
particular attention to the fuel and break-in requirements for the
engine. The advanced design of the TRX 2.5R Racing Engine does

not follow old-fashioned thinking regarding fuel and
break-in procedures.

Even if you are an experienced R/C enthusiast, it’s

Traxxas Support

Traxxas support is with you every step of the way.
Refer to the next page to find out how to contact
us and what your support options are.

Quick Start

This manual is designed with a Quick Start path
that covers only the necessary procedures to get your model
up and running in the shortest time possible. If you are an
experienced R/C enthusiast you will find it helpful and fast.
Be sure and read through the rest of the manual to learn
about important safety, maintenance, and adjustment
procedures. Turn to page 7 to begin.

2 •Revo

Before You Proceed

Carefully read and follow all instructions in this and any accompanying
materials to prevent serious damage to your Revo. Failure to follow
these instructions will be considered abuse and/or neglect.

Before running your Revo, look over this entire manual and examine the
truck carefully. If for some reason you decide Revo is not what you
wanted, then do not continue any further. Your hobby dealer absolutely
cannot accept a Revo for return or exchange after it has been run.

Warnings, helpful hints, & cross-references

Throughout this manual, you’ll notice warnings and helpful hints
identified by the icons below. Be sure to read them!

An important warning about personal safety or avoiding
damage to your Revo and related components.

Special advice from Traxxas to make things easier and more fun.

Refers you to a page with a related topic.

Support

If you have any questions about your Revo or its operation,
call the Traxxas Technical Support line toll-free at:

1-888-TRAXXAS (1-888-872-9927)

Technical support is available Monday through Friday from 8:30 am
to 9:00 pm central time. Technical assistance is also available at
www.Traxxas.com. You may also e-mail customer support with your
question at [e-mail]. Join hundreds of Traxxas R/C
enthusiasts in our online community at Traxxas.com.

Traxxas offers a full-service, on-site repair facility to handle any of
your Traxxas service needs. Maintenance and replacement parts
may be purchased directly from Traxxas by phone or online at
www.BuyTraxxas.com. You can save time, along with shipping
handling costs, by purchasing replacement parts from your local dealer.

*

and

Traxxas
1100 Klein Road
Plano, Texas 75074
Phone: [phone]
Toll-free 1-888-TRAXXAS

Traxxas U.K.
P.O. Box 1128
Winterbourne, Bristol
BS17-2SH
England
Phone: [phone]

Internet
www.Traxxas.com
E-mail: [e-mail]

Entire contents ©2004 Traxxas.
Traxxas, Revo, TRX 2.5R Racing
Engine, TQ-3, Top Fuel,
EZ-Start, Ready-To-Race,
Ready-To-Win, and ProGraphix
are trademarks or registered
trademarks of Traxxas. Other
brand names and marks are
the property of their
respective holders and are
used only for purposes of
identification. No part of this
manual may be reproduced
or distributed in print or
electronic media without the
express written permission
of Traxxas.

*Toll-free support is available to U.S. residents only.

Revo •3

Safety Precautions

All instructions and
precautions outlined in this
manual should be strictly
followed to ensure safe
operation of your Revo.

Revo is not intended for use
by children under 16 years
of age without the
supervision of a responsible
and knowledgeable adult.

All of us at Traxxas want you to safely enjoy your new Revo. Operate
your Revo sensibly and with care, and it will be exciting, safe, and fun for
you and those around you. Failure to operate your Revo in a safe and
responsible manner may result in property damage and serious injury.
The precautions outlined in this manual should be strictly followed to
help ensure safe operation. You alone must see that the instructions are
followed and the precautions are adhered to.

Important Points to Remember

The engine, exhaust system, and brakes may become extremely
hot during use.

Model engine fuel is dangerous and highly poisonous. Always

follow all directions and precautions printed on the fuel container.

Model engine fuel, especially when in a fuel dispensing bottle, may
look like a cool drink to a child. Keep all fuel out of the reach of

children at all times. Do not place fuel containers on the ground
where children can get to them while you are driving.

Model engine fuel is flammable. Never allow smoking, sparks, heat or
flame in the presence of fuel or fuel vapors.

The engine and exhaust system may become extremely hot during
use. Be careful not to touch the parts, especially when refueling or
stopping the engine.

Because Revo is controlled by radio, it is subject to radio interference
from many sources beyond your control. Since radio interference can
cause momentary loss of control, always allow a safety margin in all
directions around your model to prevent collisions.

The engine can be loud. If the noise makes you uncomfortable, wear
ear protection. Be considerate of your neighbors by not running your
model early in the morning or late in the evening.

Most importantly, use good common sense at all times.

4 •Revo

Prolonged exposure to the engine exhaust can be harmful. Avoid
breathing the engine exhaust. Always run your Revo outdoors, in a
well-ventilated area. Never run the engine indoors.

Do not operate your Revo at night, or anytime your line of sight to the
model may be obstructed or impaired in any way.

Never operate your Revo in crowds of people or busy pedestrian
areas. Revo is large and fast, and could cause injury to those unaware
of its presence.

Tools, Supplies and Required Equipment

Your Revo comes with a set of specialty metric tools. You’ll need to purchase other items, available from your hobby dealer, to operate and maintain your model.

Supplied Tools and Equipment

For more information on
batteries, see Use the Right
Batteries on page 11.

8mm slipper clutch wrenchShock wrench 5mm turnbuckle wrench 4-way wrench

1.5mm “L” wrench 2.0mm “T” wrench 2.5mm “T” wrench

RX Power Charger

RX Power plug (transformer)

2.5mm “L” wrench

RX battery power pack

(installed in model)

Suspension multi-tool

Foam air filter oil and

extra oiled air filter element

Required Tools and Equipment

10% quart - #5010
20% quart - #5020
10% gallon - #5060
20% gallon - #5070

Traxxas Top Fuel

see page22

™

8 AA alkaline batteries

NiCad or NiMh

7.2V battery pack

(see page 23)

Glow plug and

wheel nut wrench

Long Travel rocker and spring set

Suspension tuning shims

and hollow balls

NiCad or NiMh

battery charger

A peak-detecting charger
is recommended for best
performance and longest
battery life. Inexpensive
wall chargers may also be
used with very good
results. For more
information, see Use the
Right Charger on page 26.

Recommended Equipment

These items are not
required for the operation
of your model, but are a
good idea to include in any
R/C toolbox:

• Safety

glasses

• Thin, hobby-quality
cyanoacrylate instant tire
glue (CA glue)

• Side cutters or needle
nose pliers

Fuel dispensing bottle

After-run oil to protect

the engine from corrosion

Hobby knife

Philips screwdriver

Small flat-blade screwdriver

for tuning (1/8 inch blade)

Revo •5

Anatomy of Your Revo

EZ-Start Motor

Roll hoop

TRX 2.5R Racing Engine

see pg. 19 for details

Exhaust Header

Fuel Line

Pressure Line

EZ-Start Plug

Bumper Mount

Body Mount Post

Pipe Hanger

Tuned Pipe

Access Plug

(for two-speed adjustment)

Slipper
Clutch

Spur

Throttle/Brake

Servo (inside box)

Gear

Transmission

Air Filter

Shifting Servo

(inside box)

Shift Rod

Hex Hub

Axle Carrier

Pivot Ball

Steering Servo

Suspension Arm

Chassis

Push Rod

Rocker

Skid Plate

Bumper

Differential

(under chassis)

Bulkhead

(under chassis)

Oil Shock (Damper)

Spring Pre-load Adjuster

Engine Shut-off Clamp

Fuel Tank

Driveshaft (Half Shaft)

Fuel Cap

6 •Revo

Fuel Cap

Handle

Antenna Mount

Disc Brake

Receiver Box

5-cell RX Power Pack

(inside box)

Brake Tension
Adjuster

Charging Jack

(underneath)

Steering Servo

On/Off Switch

Toe Link (Turnbuckle)

OptiDrive

™

Electronic

Shift Module

Quick Start: Getting up to Speed

The following guide is an overview of the procedures for getting your Revo running, from opening the box to breaking in and tuning your engine.

Refer to the pages indicated for details on each step. Look for the Quick Start logo on the bottom corners of Quick Start pages.

1. Read the safety precautions on page 4

For your own safety, understand where carelessness and misuse
could lead to personal injury.

2. Charge the EZ-Start battery pack • See page 26

The EZ-Start requires a fully charged 7.2-volt battery
pack (not included).

10. Range test the radio system • See page 17

Follow this procedure to make sure your radio system works properly
at a distance and that there is no interference from outside sources.

11. Fill the fuel tank • See page 22

Use your fuel-dispensing bottle to fill the tank.

The Quick Start Guide is
not intended to replace
the full operating
instructions available in
this manual. Please read
this entire manual for
complete instructions
on the proper use and
maintenance of
your Revo.

3. Charge the RX Power Pack • See page 12

The 5-cell receiver battery is already installed in the truck. Plug the
supplied charger into the charging jack on the truck.

4. Install the antenna • See page 13.

Install the antenna mast in Revo.

5. Decal and Install the body • See page 8

You will need to use the body during break in, so it's best to apply
any additional decals before you use the body.

6. Install batteries in the transmitter • See page 11

Revo requires 8 AA alkaline or rechargeable batteries
for the transmitter.

7. Install the EZ-Start battery • See page 26

Install and connect a charged 7.2-volt battery pack in
the EZ-Start controller.

8. Turn on the radio system • See page 16

Make a habit of turning the transmitter on first, and off last.

9. Check servo operation • See page 17

Make sure the throttle, shifting, and steering servos are working
correctly.

12. Connect the EZ-Start to the model • See page 27

Learn the proper way to use the EZ-Start electric starting system

13. Start the engine • See page 28

Learn to use the correct starting procedure for your TRX 2.5R.

14. Break-in your engine • See page 28

Follow the break-in instructions exactly to ensure the
best-performing, longest-lasting engine.

15. Tune your engine • See page 30

Learn how to set the fuel mixture needles for optimum
engine performance.

16. Drive your Revo • See page 33

Learn to use the two-speed and reverse function on your truck,
along with important driving precautions.

17. Maintaining your Truck • See pages 40-41

Follow these critical steps to maintain the performance of your
Revo and keep it in excellent running condition.

Look for the Quick Start
logo at the bottom of
Quick Start pages.

Revo •7

Gluing the Tires and Decorating your Revo

Always wear safety glasses
to prevent glue from
splattering into your eyes.

The acetone in fingernail
polish remover will
remove excess glue from
your fingers.

For best results while
gluing, clean the bead of
the tires and the grooves
of the wheels with
denatured alcohol before
applying glue. This
removes any mold release
agent residue from the
tires and wheels,
providing a better bond.

Tire Gluing

The factory tires on your Revo are already glued to the rims. The tires
must be glued to the rims to prevent the rims from spinning inside the
tires. The instructions here are provided to show you how to glue
replacement tires to the rims in the future. Use CA tire glue available
from your local hobby dealer. You can glue the tires without removing
the wheels from the truck. For clarity, these instructions show the
process with the wheels removed.

1. Remove a wheel from Revo

using the larger (8mm) end of
the glow plug (universal)
wrench.

2. Use your thumb to push the side

of the tire away from the rim.
Place one or two drops of CA
glue into the opening and
release the tire. Capillary action
will draw the glue around the
bead of the tire.

3. Repeat step two at four or five

points around the rim, until the
tire is completely secured to the
rim. Turn the rim over and repeat
the process for the inside of the
rim/tire. Repeat for the other 3
wheels.

Applying The Decals

The main decals have already been
applied to your Revo. The extra decals
provided are die-cut for easy removal.
Use a hobby knife to lift the corner of
a decal and remove it from the
backing.

Carefully position the decal over the
desired location and press one side on
the body. Pull the decal tight and use
a finger to gradually smooth out any
air bubbles as you apply the decal.

Look at the photos on the box for
typical decal placement.

8 •Revo

4. Reinstall the wheels, make sure

none of the axle pins have fallen
out from behind the hex hubs.

CH3

CH2

CH1

The Traxxas TQ-3 Radio System

Your Revo is equipped with the TQ-3 radio system. The TQ-3 is a 3-channel system that provides up to a quarter mile range and control for up to three
servo outputs. Revo is equipped with two high-torque steering servos connected via a “Y” plug adapter (one input, two equal outputs). The TQ-3 works
in conjunction with the OptiDrive
(channels). The OptiDrive monitors the voltage of the on-board RX Power Pack. The "Function" LED will flash red if the battery voltage is too low.

TQ-3 Transmitter

Antenna

Throttle Trim

Steering Trim

™

Electronic Shift Module to monitor and control the input and output signals for the throttle and shifting servos

Revo Wiring Diagram

Throttle Neutral Adjust

Steering Wheel

Charging Jack

(to charger)

Antenna

On/Off
Switch

Receiver

RX Power Pack

5-cell NiMh

Battery

The OptiDrive ESM is
designed to adapt and
work with aftermarket
three channel radio
systems (see page 15).

Reverse Shift

Forward Shift

Throttle
Trigger

Power Switch Power IndicatorBattery Compartment

Servo Reversing

Switch

OptiDrive ESM

(Electronic Shift

Module)

To Transmission

(OptiDrive sensor)

Battery
Channel 1
Channel 2
Channel 3

Steering Servos

Shifting Servo

(micro servo)

Throttle Servo

Revo •9

The Traxxas TQ-3 Radio System

Channel

Frequency

Band

Flag

Color

Traxxas
Part No.

1 26.995 Brown 2031

2 27.045 Red 2032

3 27.095 Orange 2033

4 27.145 Yellow 2034

5 27.195 Green 2035

6 27.255 Blue 2036

Learn terms related to the
TRX 2.5R Racing Engine
beginning on page 20.

10 •Revo

Radio System Terminology

Please take a moment to familiarize yourself with these radio-system
terms. They will be used throughout this manual.

5-Cell Pack – Another term for RX Pack. The RX pack is made up of five

2/3 AA rechargeable NiMH battery cells.

Channel - The 27 MHz frequency band is divided into 6 channels so that

up to six models can be operated simultaneously. Each channel is
referred to by its flag color

Clearing your frequency - A routine, verbal check to make sure nobody

else in your area is operating on the same channel. Always clear your
frequency by calling out your channel number before operating your
model. Wait or move to another area if your channel is already being
used.

Crystal (X-tal) - The plug-in device that determines which channel the

radio system will operate on. For each channel, there are two crystals,
one for the receiver and one for the transmitter. Of those two crystals,
the one marked with the lower number (.455 MHz lower) must be
inserted into the receiver.

Frequency band - The radio frequency used by the transmitter to send

signals to your Revo. All Traxxas RTR models operate on a 27 MHz
frequency band.

mAh – Abbreviation for milliamp hour. Measure of the capacity of the

battery pack. The higher the number, the longer the battery will last
between recharges.

and channel number, as shown below.

Neutral position - The standing position that the servos seek when the

transmitter controls are at the neutral setting.

NiCad - Refers to rechargeable, nickel-cadmium batteries. The most

economical choice, since they may be recharged up to 500 times.

NiMh – Abbreviation for Nickel Metal Hydride. This is the type of

rechargeable battery used to power the radio system in the model.
These batteries are generally more efficient with less memory effect
than NiCad batteries.

OptiDrive

ESM – Electronic Shift Module. The onboard electronic

controller that monitors vehicle speed and throttle position in order to
control the action of the shifting servo. Also includes low battery
indicator for the onboard receiver pack (RX Power Pack).

Receiver - The radio unit inside your Revo that receives signals from the

transmitter and relays them to the servos.

RX Pack – RX is a common abbreviation for the radio receiver and items

associated with it. RX-Pack denotes the rechargeable battery pack used
to power the radio system in the model.

Servos - Small motor units in your Revo that operate the throttle,

shifting, and steering mechanisms.

Three-channel radio system - The TQ-3 radio system, consisting of the

receiver, the transmitter, and the servos. The system uses three
channels: one to operate the throttle, one to shift the transmission,
and one to operate the steering.

Transmitter - The hand-held radio unit that sends throttle and steering

instructions to your Revo.

Trim - The fine-tuning adjustment of the neutral position of the servos,

made by turning the throttle

and steering trim

knobs on the face of

the transmitter.

Y Adapter – Servo cable adapter that takes one input signal and directs

it to two equal output signals. Used to connect dual steering servos to
the channel one receiver output.

Installing Transmitter Batteries

CH3

CH2

CH1

Your TQ-3 transmitter uses 8 AA batteries. The battery compartment is
located in the base of the transmitter.

The Traxxas TQ-3 Radio System

4. Turn on the transmitter and check the power indicator for a

solid red light.

If the power indicator light flashes, then the transmitter batteries are
weak, discharged or possibly installed incorrectly. Replace with new or
freshly charged batteries. The power indicator light does not indicate
the charge level of the RX Power Pack installed in the model.

Use the Right Batteries

Your transmitter uses AA
batteries. Use new alkaline
batteries, or rechargeable
batteries such as NiCad or
NiMh (Nickel Metal Hydride)
batteries in your
transmitter. Make sure
rechargeable batteries are
fully charged according to
the manufacturer’s
instructions.

If you use rechargeable
batteries in your
transmitter, be aware
that when they begin
to lose their charge, they
lose power much more
quickly than regular
alkaline batteries.

1. Remove the battery compartment door by pressing the tab and

lifting the door up.

2. Install the batteries in the correct orientation as indicated in the

battery compartment.

3. Reinstall the battery door and snap it closed.

Caution: Discontinue
running y
first sign of weak batteries
(flashing red light) to avoid
losing control.

If the power indicator
doesn’t light red, check the
polarity of the batteries.
Check rechargeable
batteries for a full charge.

our Revo at the

Revo •11

The Traxxas TQ-3 Radio System

Important: When a
rechargeable battery
pack begins to lose its
charge, it will lose power
much quicker than non­rechargeable batteries.
To prevent losing control
of your model, you must
stop driving immediately
at the first sign of weak
batteries. A flashing red LED
on the OptiDrive ESM
indicates low voltage.

Other indications of weak
on-board batteries
include sluggish steering
response and shortened
radio range.

Charger Specifications:

Input voltage:

10.6/16v (min/max)

Fast charge current:

750/1000mA (min/max)

Slow (trickle) charge current:

22/55mA (min/max)

Delta Peak:

10mv

Maximum charge time:

90 minutes

Charging the Receiver Batteries

To power the radio system
in the truck, your Revo is
equipped with the RX
Power Pack, a rechargeable
5-cell nickel metal hydride
(NiMh) battery pack. The RX
Power Pack must be fully
charged before running the
truck. The supplied RX
Power Charger is a peak­detecting unit that will
charge the supplied RX
Power Pack in about 1 hour.

The peak detection circuitry
automatically shuts off the charger when the maximum charge has been
achieved. Revo has a built in charging jack so you do not have to remove
the battery pack from the model. The long charger cord allows easy
handling of the truck while the battery is charging.

1. The RX Power Charger can operate on either A/C or D/C power*. An

A/C power supply is supplied with Revo. Plug the end of the A/C
adapter into the back of the charger.

2. Plug the A/C power supply into any 110 volt wall outlet. The charger

light should glow steady green (no battery connected).

3. Plug the charger output cord into the charging jack located under the

right front of the truck. The charging jack is
protected by a rubber plug.

4. The green light on the charger should begin

to flash quickly indicating that fast charging
is in progress.

5. When the light turns solid green (not

flashing) the battery pack is fully charged
and ready for use.

6. Put the rubber plug back over the charging

jack on the truck.

After fast charging has completed, the RX
Power Charger continues to charge in
trickle (slow) charge mode. It will continue
until the battery is disconnected. The RX
Power Charger will automatically shut off
after 90 minutes of fast charging time.
When the charger is not in use, wind the
charging cord around the cord holder.
To secure the cord, insert the end of it into
the retaining slot on either end of the cord holder. The RX Power
Charger is equipped with mounting holes in the back of the
case to allow convenient, out-of-the-way wall mounting.

The RX Power Charger can be powered by our
optional D/C car adapter. It features a tangle­free, extra long wire and integrated fuse. The
long charging cord allows the model to remain
outside the car while charging. Caution! Never

charge batteries in an enclosed car interior or
while driving. Never leave charging batteries
unattended. Monitor them closely.

Battery Care

Some precautions should be taken to maintain the performance of the
rechargeable NiMh receiver pack in your model. Improper use of the
battery pack could result in personal injury or damage to your truck.

Only use approved chargers for NiMh battery packs (such as the Traxxas
RX Power Charger). Do not exceed the maximum charge rate of 1 amp.
Do not short circuit the battery pack. This may cause burns and severe
damage to the battery pack
Do not burn or puncture the batteries. Toxic materials could be released.
If eye or skin contact occurs, flush with water.
Store the battery pack in a dry location, away from heat sources and
direct sunlight.
Nickel Metal Hydride batteries must be recycled or disposed of properly.
Do not completely discharge the RX Power Pack or you could damage
it. Do not use dischargers on the pack. Store the battery with at
least 25% charge. Stop running and recharge at the first indication
of reduced voltage.

12•Revo

* With optional D/C car adapter

Setting up the Antenna

1. Locate the black antenna wire that exits the receiver cover. The

receiver cover is mounted on the top of the chassis, near the front.
The antenna wire exits the cover just ahead of the fuel tank.

2. Pull the wire straight with your fingers and then insert the end of

the wire into one end of the antenna tube. Push the wire all the way
through the antenna tube.

3. Insert the base of the tube into the molded post on the side of the

radio box.

4. Place the antenna tip over the top of the tube to secure the

antenna wire.

Antenna Tip

The Traxxas TQ-3 Radio System

Spray a little window
cleaner on the antenna
wire to make it easier
to push through the
antenna tube.

Don’t shorten the length
of the antenna wire. Its
length is tuned to the
frequency band; cutting it
could severely shorten the
radio system’s range.

5. On the transmitter, always fully extend the telescoping antenna when

running your Revo. Make a habit of holding the transmitter so that the
antenna points straight up.

Antenna Tube

Front of

Truck

Don’t push the
transmitter antenna down
from the top. Pull it down
from the bottom, one
segment at a time, to
prevent binding and
kinking the antenna mast.

Revo •13

Steering

T

U

R

N

L

E

F

T

T

U

R

N

R

I

G

H

T

Brake

Neutral

Accelerate

CH.3

CH.2

CH.1

Shift Reverse

Shift Forward

The Traxxas TQ-3 Radio System

TQ-3 Radio System Controls

TQ-3 Radio System Adjustments

In addition to the electronic throttle and steering trim controls, your
radio system features throttle neutral adjustment and servo reversing
switches.

Throttle Neutral Adjustment

The throttle neutral adjustment is located on the transmitter face and
controls the forward/reverse travel of the throttle trigger. Change the
adjustment by pressing the button and sliding it to the desired position.
There are two settings available:

50/50: Allows equal travel for both acceleration and braking.
70/30: Allows more throttle travel (70%) and less

brake travel (30%).

50/50 is the required setting for Revo with the TRX 2.5R Racing Engine.

Electronic Throttle Trim

The electronic throttle trim located on the face of the transmitter adjusts
the neutral (center) point of the throttle servo when the servo is at rest.
This control has been preset for you at the factory. If necessary, adjust
the control so that the carburetor is at idle, and the brakes are not
applied (the model will roll freely). Do not use the throttle trim to raise
or lower the engine idle speed. Make the idle speed adjustment on the
carburetor.

14 •Revo

Electronic Steering Trim

The electronic steering trim located on the face of the transmitter
adjusts the neutral (center) point of the steering servos when the servos
are at rest. Adjust this control to make the model drive straight with no
steering input at the wheel.

CH.3

CH.2

CH.1

The Traxxas TQ-3 Radio System

Servo Reversing Switches

The servo reversing switches are located on the front of the transmitter,
next to the on/off switch. Moving a switch reverses the direction of the
corresponding servo. Each switch corresponds to a channel, as shown
below. For example, if you turn the steering wheel to the right and your
front wheels turn left, you would move the channel 1 switch to correct
the servo direction. It may be necessary to adjust the corresponding trim
control after
moving a switch

.

The default
position for the
servo reversing
switches is
shown.

TQ-3 Channel to Servo Chart

Channel Servo

1 Steering
2 Throttle and braking
3 Shifting

Programming the OptiDrive™ESM

The OptiDrive ESM electronically monitors
vehicle speed and controls forward and reverse
shifting. Controlling the shift action electronically
rather than by mechanical systems reduces the
number of components in the transmission. The
transmission weighs less, there is lower
rotational mass for quicker acceleration, and
constant drive engagement for smooth power delivery.

The OptiDrive module prevents the transmission from changing
directions while the truck is in motion. The truck must be completely
stopped to change directions, regardless of the position of the shift
selector switch on the transmitter. The OptiDrive module is preset at the
factory. If the transmitter throttle trim adjustment is changed, then the
OptiDrive module will need to be re-programmed.

1. The engine must be shut off. The radio system must be on (receiver

and transmitter).

2. Set the TQ-3 Transmitter to its factory default shift settings:

Set the THROTTLE NEUTRAL switch to the 50/50 setting.
Set the THROTTLE TRIM to the center “0” setting, then adjust the
THROTTLE TRIM until the carburetor closes.
Set the CHANNEL 2 SERVO REVERSING SWITCH to the right position.
Set the CHANNEL 3 SERVO REVERSING SWITCH to the right position.
DO NOT change the position of any of the servo reversing switches
after programming the OptiDrive. If settings were changed after
programming the OptiDrive, it will have to be reprogrammed.

3. With the throttle at neutral, press and hold the

SET button until the Function LED flashes green
twice and then release the button immediately.
You are now in programming mode.

4. Pull the transmitter throttle

trigger to the full throttle
position. Hold it there until the
Function LED flashes green
three times. Note: The throttle
servo will not move during programming even though it is connected
to the controller.

5. Release the transmitter throttle

trigger allowing it to return to
neutral. The Function LED will
turn solid green, indicating that
the shifting servo is OK to shift
and the programming has been completed. The controller is now
programmed and ready to go!

If the transmitter throttle settings are changed, it will be necessary
to complete the programming sequence again.
If the SET button is released before the Function LED flashes
green twice in step 3, the OptiDrive will return to the normal
operation mode.
If you experience any problems during programming, turn the
receiver off, then on again, and repeat the programming steps.

For instructions on how to use the OptiDrive with aftermarket radio
systems, or to access advanced programming options, visit our website,
www.Traxxas.com.

Large adjustments to the
throttle trim and/or throttle
linkage may require
re-setting the OptiDrive
ESM to maintain proper
shifting action.

For transmission durability,
the OptiDrive ESM limits
the model’s reverse speed
to about 70% of full
throttle. If settings are
changed, and you notice a
decrease in forward top
speed, you could have the
OptiDrive system reversed.
Return the TQ-3 servo­reversing switches for
channels two and three
back to their default
settings and re-program the
OptiDrive Module. For
programming with
aftermarket radio systems,
please see our website.

OptiDrive Operation

• Green “Function”

Shift allowed

• Red flashing “Function”

Low battery, see pg. 12

• Red “Sensor”

Sensor circuit is broken.
Possible disconnected
sensor, broken wires, or
damaged sensor.

• Blue flashing “Sensor“

Normal operation as
vehicle moves. Indicates
signal pulse from sensor.
Depending on the rotor
position, solid blue or off
when vehicle is at rest.

Revo •15

Channel 1

Brown

Channel 2

Red

Channel 3

Orange

Channel 4

Yellow

Channel 5

Green

Channel 6

Blue

CH3

The Traxxas TQ-3 Radio System

Remember, always turn the
TQ-3 transmitter on first and
off last to avoid damage to
your Revo. Never turn the
radio off while the engine is
running.

TQ-3 Radio System Rules

Each time you prepare to run your Revo,
you must clear your frequency to be sure
no one else in the area is using the same
channel as you.

There are six possible channels, numbered
1 through 6. Each is represented by a color.
Look at the crystal plugged into the back of
your transmitter to determine which
channel your truck is assigned to.

Always turn your TQ-3 transmitter on first
and off last. This procedure will help to prevent your Revo from
receiving stray signals from another transmitter, or other source,
and running out of control.

Always have the transmitter and receiver turned on before you start
the engine. Never turn the radio system off while the engine is
running. The on/off switch in the model only turns the receiver on
and off. It does not turn off the engine.

Always use new or freshly charged batteries for the transmitter, and
make sure the on-board 5-cell NiMh battery pack is fully charged. The
function light on the OptiDrive will flash red if the 5-cell battery pack
requires charging. Weak batteries will limit the range of the radio
signal between the receiver and the transmitter. Loss of the radio
signal can cause you to lose control of your Revo.

16•Revo

1

Always turn your transmitter on first. Always turn your receiver on second. Then start your engine.

2 3

The Traxxas TQ-3 Radio System

Using the TQ-3 Radio System

The TQ-3 Radio System was pre-adjusted at the factory. The adjustment
should be checked before running the model, in case of movement
during shipping. Here’s how:

1. Fully extend the chrome antenna mast on the transmitter and turn

the switch on. The red indicator light on the transmitter should be
solid red (not flashing).

2. Turn on the receiver switch in the model. The switch is located in the

top of the radio compartment. The function light on the OptiDrive
ESM should be green. A red flashing LED indicates low voltage in the
RX Power Pack. The sensor LED is intermittent depending on the
rotor position.

3. Position Revo so that its front wheels are off the ground.

4. Turn the steering wheel on the transmitter back and forth and check

for rapid operation of the steering servo. Also, check that the steering
mechanism is not loose or binding. If the steering operates slowly,
then check the receiver pack to make sure it is fully charged.

5. When looking down at model, the front wheels should be pointing

straight ahead. If the wheels are turned slightly to the left or right,
slowly adjust the steering trim control on the transmitter until they
are pointing straight ahead.

6. Operate the throttle trigger on the transmitter and check for rapid

operation of the throttle servo. When the throttle trigger is pulled
back, the carburetor should open (slide moves out). When the
throttle trigger is pushed all the way forward, the brake should lock.

7. Operate the shift button on the transmitter and check for rapid

operation of the shifting servo. Push the shift button down for
forward. The servo will operate the spring-loaded shift mechanism
and you will hear the transmission click into forward. Push the shift
button up for reverse and you will again hear the transmission

click

and shift into gear.

8. Once adjustments are made, turn off the receiver on your Revo,

followed by the hand-held transmitter.

Range-Testing the TQ-3 Radio System

Before each running session with your Revo, you should range-test your
radio system to ensure that it operates properly.

1. Turn on the radio system and check its operation as described in the

previous section (Using the TQ-3 Radio System).

2. Have a friend hold the model with the engine off.

3. Make sure your transmitter antenna is fully extended, and then walk

away from the model with the transmitter until you reach the farthest
distance you plan to operate the model.

When the engine is
running, don’t use the
throttle trim on the
transmitter to adjust the
engine idle speed. Instead,
use the idle speed
adjustment on the
carburetor.

Don’t attempt to operate
your Revo if there are any
problems with your radio
system or radio interference
at your location.

4. Operate the controls on the transmitter once again to be sure that

the model responds correctly.

5. Do not attempt to operate the model if there is any problem with the

radio system or any external interference with your radio signal at
your location.

Revo •17

Traxxas strongly
discourages changing or
modifying any part of the
TRX 2.5R Racing Engine.
Old tech tips and tricks that
may have boosted the
power of other engines
could seriously diminish
the performance of the
TRX 2.5R Racing Engine.

There’s more advanced
thinking, development and
testing in the stock parts of
your TRX 2.5R Racing
Engine than in many
aftermarket manufacturer’s
performance parts. The
TRX 2.5R Racing Engine is
already the most powerful
engine in its class and
simply will not benefit
from average, low-tech,
aftermarket bolt on
performance items.

The TRX 2.5R Racing Engine

Introduction

There’s nothing like the TRX 2.5R Racing Engine in your new Revo.
The TRX 2.5R Racing Engine is a specialty high-performance racing
engine. Its impressive performance is the result of years of focused
engineering development, and thousands of hours of controlled testing
and rigorous real-world running. It offers unprecedented power and
performance that turns ready-to-run into Ready-To-Race

The TRX 2.5R Racing Engine takes a total-system approach. Each part of
the engine, from the air filter to the exhaust tip, is carefully engineered
to work in harmony with other engine components. Each part
complements the next, to extract maximum power. The TRX 2.5R Racing
Engine is designed to be tolerant of variations in tuning, and to run
successfully through a wide range of variable atmospheric conditions
such as changes in temperature, humidity, and altitude.

In order to get the longest engine life and keep the TRX 2.5R Racing
Engine in top running condition, it is very important to perform regular
routine maintenance. The number one cause of premature engine

wear and failure is lack of care and maintenance!

Break In

The TRX 2.5R Racing Engine is manufactured to exacting tolerances and
requires a specially-designed break-in procedure to accomplish the final
precision fitting of the internal engine components. It is very important
that you follow the new break-in procedure as closely as possible to
achieve the best performance and longest life from your TRX 2.5R Racing
Engine. Engine break-in will take between one and two hours. Old style
break-in procedures, such as idling the engine on the bench for several
tanks of fuel or simply running the engine with a very rich fuel mixture
for the first 4 tanks of fuel, will not achieve the best results. Follow the
easy steps in this manual.

®

.

After-Run Maintenance

Perform after-run maintenance on the engine to prevent corrosion
from building up on the internal engine components. The fuel
naturally attracts moisture and corrosion can build up very quickly
inside the engine if it is not prevented.

A few minutes spent before and after each time you run your model
will allow you to enjoy it for a long time to come. Read on for more
exciting details about your new engine.

18 •Revo

Air Filter Maintenance

A clean air filter is critical for long engine life. Due to the high-
performance nature of the TRX 2.5R Racing Engine, a tremendous
amount of vacuum is created to move a large volume of high-velocity air
through the carburetor. Dirt is the worst enemy to your engine. Clean
the air filter after each hour of running to prevent sucking dirt into the
engine. Extra pre-lubed filter elements have been provided to encourage
you to maintain your air filter.

The TRX 2.5R Racing Engine

TRX 2.5R Racing Engine Illustrated

Air Filter
Housing

High-Speed
Needle

Fuel Intake

Air Intake

Carburetor

Flywheel

Clutch Bell

Exhaust Tip
Tuned Pipe

Pressure Line

Fuel Line

Air Filter
Base

Idle Speed
Screw

Crankshaft

Glow Plug Wire

Negative Wire

EZ-Start Plug

Ground Wire
Positive Wire

Head Protector

PowerTune

™

head

(Cylinder head)

EZ-Start Drive Unit

EZ-Start Motor

Low-Speed Needle

Engine Mount

Crankcase

Throttle Arm

EZ-Start

Controller

Revo’s fuel tank is equipped
with a built-in sintered
bronze fuel filter.

Header

Engine

Shut-off

Clamp

Fuel Tank

Revo •19

The TRX 2.5R Racing Engine

20 •Revo

Terms to Know

You’ll find these Nitro R/C engine terms throughout this section of the manual.
.15 - .15 or “15” refers to the displacement of the engine. The TRX 2.5R

Racing Engine is .15 cubic inches or 2.5 cubic centimeters (cc). The name
“TRX 2.5R” is derived from the cc measurement.

ABC - Abbreviation for aluminum, brass, and chrome. Refers to engine

construction that consists of an aluminum piston that slides in a chrome­plated brass sleeve. The TRX 2.5R Racing Engine uses ABC construction.

Air filter - The air filter sits atop the carburetor and prevents harmful dust

and dirt from entering the engine. Dirt ingestion is the number one cause
of premature engine failure so the engine should never be run without the
air filter in place.

Big Block .15 - A .15 (2.5) engine that uses a larger crankcase size and longer

stroke than typical .15 engines. Generally only used for specific racing
classes.

Break-in - Break-in is the procedure for running a brand new engine

according to specific instructions. This correctly prepares the engine for
normal running. The break-in procedure can be different for different
makes of engines. Follow the Traxxas directions for break-in exactly.

Carb - Abbreviation for carburetor.
Carburetor - The carburetor atomizes (mixes) the fuel with the air so that

the engine can burn it. There are two types of carburetors, slide carbs and
barrel carbs. The TRX 2.5R uses the superior slide carburetor design.

Clean-out - Cleaning-out is a condition that occurs when the engine is

accelerating and the fuel mixture becomes sufficiently lean to allow the
engine to continue into its upper RPM power band. Usually characterized
by a noticeable decrease in blue e
engine speed.

Combustion chamber - The combustion chamber is machined into the

bottom of the cylinder head. This is where the glow plug ignites the fuel.
The shape of the combustion chamber is designed to promote more
efficient burning of the fuel.

Connecting rod - The connecting rod transfers the piston motion to the

crankshaft. The TRX 2.5R Racing Engine uses a “knife-edged” connecting
rod. The aerodynamic, sharpened edges allow it to “slice” through the
pressurized air/fuel mixture inside the crankcase.

Cooling fins - The cooling fins are molded into the cylinder head and

crankcase and cause heat to be drawn away from the engine. Heat is

haust smoke and a dramatic increase in

x

removed when it dissipates into the air passing across the cooling fins.
It is important to keep the fins clean of dirt and debris for maximum
cooling efficiency.

Crankcase - The engine “body” that contains all of the running

mechanical components.

Crankshaft - The main shaft of the engine that contains the

rotating assembly.

Cylinder head (head) - The finned aluminum part on top of the engine that

is responsible for dissipating most of the engine’s heat. The combustion
chamber is machined into the bottom of the head.

Damper - Another term for shock.
Damping - Resistance force caused by the piston moving through the oil

used to absorb bump and spring rebound energy.

Dyno - Abbreviation for dynamometer. A precise piece of testing equipment

that accurately measures engine power and torque output over the
engines entire RPM range.

EZ-Start - Second generation Traxxas on-board electric starting system. The

system consists of a hand held starter control unit and an on-board
gearbox with an electric motor to spin the engine.

Filter foam - The oiled foam element inside the air filter housing. The filter

foam in the TRX 2.5R Racing Engine must be thoroughly cleaned and re­oiled after every hour of run time.

Fit - Usually refers to the fit of the piston and sleeve. If the fit is tight, then

the piston will feel very tight at top of the sleeve and the engine will have
good sealing and compression. If the fit is loose, then compression will be
low and the piston and sleeve should be replaced.

Flame-out - Occurs when the engine stops running at high RPM. Usually the

fault of an excessively lean fuel mixture or glow plug failure.

Fuel - (10% 20%) The TRX 2.5R must have model engine fuel to run. Traxxas

Top Fuel is recommended. Fuel is sold in quarts and gallons from hobby
dealers. The 10 and 20% labeling refers to the percentage amount of
nitromethane contained in the fuel (see “nitro percentage” definition).

Fuel mixture - The ratio of fuel to air as determined by the needle settings

of the carburetor.

Fuel tubing (fuel line) - The thick silicone tubing that carries fuel from the

fuel tank to the carburetor.

Glow plug - The glow plug is located in the cylinder head at the top of the

combustion chamber. It contains a platinum element that glows red hot

The TRX 2.5R Racing Engine

when voltage is applied. When the engine is being started, the heat from
the glow plug ignites the fuel mixture and starts the combustion process.

Glow plug driver - This tool clips onto the glow plug and supplies the

required voltage to light the glow plug element. It is also called an igniter.
EZ-Start equipped engines do not require this separate tool.

Header - The aluminum tube that connects the tuned pipe to the engine

exhaust port. The length and diameter of the header must be carefully
selected to extract the most power from the engine.

High-speed needle - Adjusts the carburetors fuel/air mixture at high RPM.
Idle speed - The speed (RPMs) the engine runs at when the transmitter’s

throttle trigger is at neutral.

Idle speed screw - Located on the carburetor body. This screw adjusts the

idle RPM of the engine.

Lean - A running condition where the engine is not getting enough fuel (for

the available air). Symptoms include engine overheating, or the engine
runs for a short time and then stalls, particularly at high speed. This is a
dangerous condition that should be corrected immediately or it can ruin
your engine.

Leaning the mixture - Turning either the high speed and/or low-speed

needle(s) clockwise to decrease the amount of fuel the engine receives.

Low-speed needle - Needle valve that controls the low-speed fuel mixture.
Needle valve - Valve consisting of a tapered needle that closes against a

corresponding seat to regulate fuel flow.

Nitro - Abbreviation for nitro methane, a component of model engine fuel

that improves fuel combustion and power output. Nitro also refers to a
class of RC powered by model engines instead of electric.

Nitro content - The amount of nitro methane used in the fuel. Usually

measured as a percentage of the total fuel volume. Traxxas engines are
optimized to use 10-20% nitro. 30% nitro may be used for racing.

Nitromethane - Nitro methane is a component in the fuel that increases

power from the combustion process up to a point. Engines are generally
optimized to use a range of nitro content for the best power.

O-ring - Rubber “O”-shaped ring used as a sealing gasket.
Pipe - Abbreviation for the tuned exhaust pipe on a nitro engine. See “Tuned

P

ip

e” definition.

Piston - The piston is the internal engine part that is attached to the upper

end of the connecting rod and moves up and down in the cylinder sleeve.
The precise fit between the piston and the sleeve creates a seal that allows

engine to have the required compression f

Port - Ports are openings in the sleeve that allow atomized fuel to enter the

combustion chamber and burned exhaust gasses to exit. The shape and
location of the ports are a large factor in controlling the engine timing and
power output.

Priming - Manually causing fuel to move from the fuel tank up to the

carburetor. This is sometimes necessary after the engine has been sitting
for a long period of time and all the fuel has drained back to the tank. On a
Traxxas model this is done by holding your finger over the exhaust tip for
one or two seconds while the engine is starting.

Punch - A term that refers to how quickly the model responds to throttle

input or how quickly it accelerates.

Rich - A running condition where the engine is getting too much fuel for the

available air. It is better to run an engine slightly rich to increase engine
life. Excessively rich mixtures cause the engine to have s
performance with exaggerated blue smoke and unburned fuel coming
from the exhaust.

RPM - Abbreviation for revolutions per minute (how many times the engine

crankshaft spins in a minute).

Sleeve - Internal engine part that contains the piston. The precise fit

between the sleeve and the piston creates a seal that allows engine to
have the required compression for combustion. The sleeve in a TRX
engine is made of brass and is then hard-chrome plated.

Slide carburetor - The throttle on a slide carburetor closes and opens by

sliding a barrel in and out of the carburetor body. This type of carburetor is
preferred for performance use because it provides a less restrictive
“straight-through” air path than the barrel carburetor design.

Stall - When the engine stops running, usually due to an incorrect fuel

mixture setting or running out of fuel.

Tuned pipe - The tuned exhaust pipe usually consists of a specially-shaped

metal or composite chamber with baffles that is designed to enhance the
power output of the engine.

Wear-in - Fitment process that occurs during engine break-in where internal

engine parts develop an even more precise matched fit through actual use
under controlled circumstances.

WOT - Abbreviation for wide-open throttle.

or combustion.

uggish

l

Revo •21

The TRX 2.5R Racing Engine

DANGER! Model engine fuel
is poisonous to humans
and animals. Drinking the
fuel can cause blindness
and death. Handle with
care and respect. Keep it
out of reach of small
children at all times! While
driving, do not leave your
fuel dispensing bottle on
the ground where a child
could have access to it.
Follow fuel label warnings.

You may use higher nitro
percentages than 20% in
certain circumstances. Call
1-888-TRAXXAS for more
information.

The Fuel

Use the Right Fuel

It’s imperative that you use the correct fuel in your
TRX 2.5R Racing Engine for maximum performance
and engine life. Traxxas Top Fuel™should be used to
ensure correct engine lubrication, performance, and
ease of tuning. Traxxas Top Fuel has been proven in
thousands of engines, so you can count on it every day
for great performance.

Top Fuel is the only fuel which is 100% certified for use in Traxxas
engines.
Traxxas Top Fuel is made with just the right balance of the highest
grade natural and synthetic lubricants to allow excellent throttle
response and the best top-end performance, without sacrificing
long-term durability.
All of the components in the fuel are carefully selected from the best
materials available and then custom blended to match the
metallurgy and temperature characteristics of Traxxas engines.

You may use 10% or 20% nitro-content fuel. Use the same percentage
all the time; don’t switch back and forth between 10% and 20% fuel. If
you break-in your engine on 20% fuel, then always use 20% fuel.

What about Other Fuels?

Can other brands of fuel be used besides Top Fuel? There are other
fuels that can provide satisfactory performance; however there could
be long-term costs in the form of decreased engine performance, loss
of tuning ease, and shorter engine life. Only use fuels that contain both
castor and synthetic oil.

Handling the Fuel

Follow all directions and warnings on the fuel can.

Keep the fuel tightly capped at all times. Some components in the
fuel can evaporate very quickly and upset the balance of the fuel.
Do not store unused fuel in the fuel dispenser. Immediately return
fresh unused fuel back into the fuel can.
Do not mix old and new fuel. Never mix different brands of fuel
together.
Store the fuel in a cool dry location, away from any source of heat,
ignition, or combustion.
Read and follow the safety precautions on page 4 in this
manual.

Filling the Fuel Tank

Use a fuel dispensing bottle (Traxxas Top Fueler, part
#5001) to put fuel into Revo’s fuel
tank. To fill the fuel bottle, squeeze
the air out, insert the dispenser tip
into the fuel can, and release your
grip on the bottle. As the bottle
expands, fuel will be drawn into it.

To fill your model, pull up on the
fuel cap handle, insert the tip of the
fuel bottle, and squeeze to dispense
the fuel.

22•Revo

Everyone has an opinion or a claim to make about fuel. The engineering
team at Traxxas spent over 2-years developing the TRX 2.5R Racing
Engine. No one knows more about the specific fuel requirements of
Traxxas engines, than Traxxas engineers. We strongly urge you not to
take chances with your engine investment and use the Traxxas fuel
made for the TRX 2.5R Racing Engine.

The TRX 2.5R Racing Engine

The Air Filter

The TRX 2.5R Racing Engine air filter is specifically designed to deliver
maximum performance while protecting your engine from dust and dirt.
Use only the supplied filter. You will not improve engine performance
by switching to an aftermarket filter, and you may risk engine damage
due to poor filtration.

The TRX 2.5R Racing Engine air filter assembly consists of 3 pieces:

1. A rubber filter base

2. A plastic housing consisting of a permanently assembled

mesh cap and body

3. An oiled foam element

You must clean the filter after every hour of run time, even if the filter
looks clean. This includes the break-in time. Clean your air filter after

break-in. Dust (which is often too fine to see) and dirt constantly move

through the filter anytime the engine is running. Even if you can’t see
dirt on the filter, it is present inside the foam after any amount of run
time. If you exceed the recommended cleaning intervals, your engine
will be damaged. Engine damage or wear due to dirt ingestion is easy to
detect, and one of the top causes of premature engine failure.

Air Filter Cleaning Instructions

1. Remove the air filter from the

carburetor bore by pulling the
entire filter assembly firmly to the
side to release it. Do not pull

straight up.

5. Oil the foam element with foam filter oil. Use the supplied Traxxas

filter oil (part# 5263) or a high-quality, special-purpose foam filter oil
like what is used for off-road motorcycle and ATV engines.This type
of filter oil is available at motorcycle pro-shops. Apply 30 drops of the
Traxxas filter oil evenly to the top, bottom and sides of the filter
element (30 total drops divided among the 3 surfaces). Squeeze the
filter element repeatedly to help spread the oil throughout. The filter
element should be evenly colored by the oil. Even color indicates
that the oil is distributed evenly. Do not squeeze out excess oil.

Note: Do not use the air filter oil for anything other than the air
filter. It is not meant to be a lubricant.

6. Reassemble the filter and install it on the engine, making sure the

rubber filter neck fits securely on the carburetor with no gaps or
air leaks.

Clean your air filter after
every hour of run time to
avoid engine damage,
even if the filter looks
clean.

If you use compressed air
to dry your air filter
assembly, wear safety
glasses and avoid directing
compressed air toward
your skin.

If foam filter oil is not
available, clean 30 or 40
weight motor oil can be
substituted, but is not
preferred. Never run the
engine without a properly
oiled filter!

2. Disassemble the filter. Pull the

rubber air filter neck out of the
filter body. With the base removed,
the foam element is visible in the
bottom of the filter body. Pull out the foam element.

3. Clean the filter parts by thoroughly washing all three pieces of the

filter assembly in hot soapy water (dishwashing detergent works
well). Repeat twice.

4. Thoroughly dry the parts with a clean towel or compressed air.

Remember to wear your safety glasses when working with
compressed air.

Revo •23

The TRX 2.5R Racing Engine

See page 31 for more
information on how air
density affects engine
tuning.

The Carburetor

Understanding the Carburetor adjustments

The carburetor performs several functions. It controls the engine’s speed
by restricting the intake of air and fuel into the engine. It atomizes the
fuel (suspends the fuel droplets in the air) and also controls the air/fuel
ratio of the mixture entering the engine (how much air for a given
amount of fuel).

To help provide a better understanding of engine tuning and why it’s
necessary, the following is a brief explanation of the air/fuel combustion
process that takes place inside the engine.

In order to create the cylinder pressure that results in power, the engine
burns the air/fuel mixture. Both air and fuel, in correct amounts, are
needed for proper combustion. It is the carburetor’s job to mix the air
and fuel together (atomize the fuel), in the correct proportion for the
best possible combustion. This is the ideal air/fuel ratio. The ideal air/fuel
ratio required for the engine remains roughly constant. Due to variations
in atmospheric conditions (temperature, humidity, altitude etc.) fuel flow
adjustment valves (called fuel mixture needles) are required to meter the
fuel and maintain the ideal air/fuel ratio in these ever-changing
conditions. For example, colder air is more dense (more air molecules)
for a given volume of air and therefore requires more fuel (more fuel

molecules) to maintain the correct air/fuel ratio. Warmer air is less dense
(fewer air molecules) and therefore needs less fuel to maintain the
correct air/fuel ratio. The tuning needles are there to adjust how much
fuel is made available for the carburetor to mix with the available air
(atomization).

The Fuel Mixture Needles

The amount of fuel metered and atomized by the carburetor is
controlled by the two mixture needles, the high-speed needle and the
low-speed needle. The low-speed needle is used to meter the fuel used
by the engine at idle and low RPM (part-throttle) engine speed. The
high-speed needle is used to meter the fuel when the throttle is open
from part throttle to wide-open throttle (WOT). Two needles on the TRX

2.5R Racing Engine provide precise control of the air/fuel ratio across the
engine’s entire RPM range.

The maximum possible fuel flow is always controlled by the high-speed
needle. It works like the main water valve on a garden hose. Turn it
clockwise to close the valve, counter-clockwise to open it. When the
throttle is at idle or partially open, the low-speed needle again meters
the fuel flow at the outlet (needle seat) where the fuel enters the
carburetor venturi. This second valve acts like the spray nozzle at the end
of the garden hose in our example. When you accelerate from idle, the
throttle opens and the low-speed needle is pulled away from the needle
seat. This allows more fuel to flow with the increased air flow. As the

24 •Revo

The TRX 2.5R Racing Engine

Water Valve

(Controls Overall Flow)

High Speed Needle

Water Nozzle

(Controls Fine Flow)

Low Speed Needle

Richen

throttle is increased, the low-speed needle is pulled completely away
from the needle seat leaving it fully open. At that point, fuel metering is
entirely controlled by the high-speed needle. Again, using our water
hose example, when the spray nozzle at the end of our garden hose is
fully open, then the main water valve can be used to adjust how fast the
water flows.

The engine’s performance is directly linked to the fuel mixture.
Richening the fuel mixture increases the amount of fuel in the air/fuel
mixture

ratio and leaning the fuel mixture decreases the amount of

fuel in the air/fuel mixture ratio.

Lean

Rich

Slightly lean fuel mixtures deliver stronger, more efficient
combustion and more power, but with less lubrication.

Slightly rich fuel mixtures deliver cooler running and more
lubrication but with slightly less power.

Tuning the engine means finding the perfect balance between the two;
excellent power to meet your needs while maintaining good lubrication
for long engine life.

The optimal fuel mixture setting is rich to provide a

safety margin against having a lean condition if some variable changes
(such as the temperature from one day to the next).

General fuel mixture settings are measured by the number of turns the
needles are turned out from fully closed. The fuel mixture settings have
been pre-set from the factory to typical break-in settings. Do not
readjust your carburetor from the factory settings until after the engine
is started and running, and you have been able to observe the engine
running to assess what minor adjustments may be required to
compensate for fuel, temperature, and altitude. Adjustments are usually
made in 1/8 or 1/16-turn increments.

The Idle Speed Adjustment

The idle speed screw controls the closed position of the throttle slide.
When the throttle servo is in its neutral position, the throttle slide should
be stopped against the idle adjustment screw. Always use the idle speed
adjusting screw to control engine idle. Do not use the throttle trim on
the transmitter to adjust idle speed. The idle speed should be set as low
as possible and still maintain reliable running.

See Tuning Your TRX 2.5R
Racing Engine on page 30

for complete information on
adjusting the air/fuel
mixture and idle speed.

Factory Needle Settings

If your factory preset
carburetor adjustments
have been tampered with,
use the following settings:

• Set the high-speed needle
to 4 turns out from closed.

• Set the low-speed needle
so the screw head (red in

) is flush (even) with

Fig. A
the end of the slide (yellow
in Fig. A).

Fig. A

Low Speed

Needle Adjustment

Always use the factory
settings for initial starting.
Only use these settings
when the factory settings
have been lost.

Revo •25

Use the Right Charger

The most convenient type
of charger is an AC peak­detecting charger that
plugs directly into an AC
wall outlet. It contains
special peak-detection
circuitry that automatically
shuts the charger off when
the battery is fully charged.

If you’re using a 15-minute
timed charger, always fully
discharge the battery pack
before each charge. Some
high mAh battery packs
(1500 mAh or higher)
require more than the
standard 15 minutes of
charge time. If the battery
pack is cold after 15
minutes of charging, add
another 5 minutes of charge
time. Closely monitor the
battery pack and stop
charging it when it begins
to feel warm to the touch.
Never leave a battery
charging unattended.
Always follow charger
manufacturer’s instructions.

The TRX 2.5R Racing Engine

The Traxxas EZ-Start Electric Starting System

The Traxxas EZ-Start brings the convenience of push-button electric
engine starting to your Revo. The EZ-Start consists of a hand-held
control unit and an on-board motorized starter.

Power for the EZ-Start system comes from a 7.2-volt rechargeable
battery pack installed in the hand-held control unit (battery
not included).

The engine glow plug is heated automatically by the EZ-Start system,
eliminating the need to keep up with a separate glow plug igniter.

The voltage to the glow plug is kept constant, regardless of the load
placed on the starter by the starter motor.

The “Glow Plug” LED (light emitting diode) on the control unit
indicates the condition of the glow plug.

The “Motor” LED indicates the status of the EZ-Start electric
starter motor.

The cush drive mechanism in the drive unit prevents damage to the
gears caused by engine kickback.

Smart Start

™

protection circuitry prevents damage to the motor by
cutting power if the load on the motor or other electronics exceeds
safe limits.

Installing the EZ-Start Battery

The EZ-Start system requires a fully charged 7.2-volt rechargeable NiCad
or NiMh battery pack (not included). Use a charger (not included)
designed for 7.2-volt battery packs. Charge the battery according to the
charger manufacturer’s directions.

1. Press the tab in the end of the battery compartment door to open.

2. Plug a fully charged 7.2-volt battery pack into the connector inside.

3. Twist the battery 2 or 3 times to twirl the battery plug wires. This

helps hold the wire and battery in place when the battery is installed
in the compartment.

4. Install the battery into the compartment and press the wires securely

into place.

5. Snap the battery compartment door back on and lock the end tab.

Inexpensive overnight wall
chargers may also be used.

26•Revo

The TRX 2.5R Racing Engine

MotorMotor

GlowGlow

PlugPlug

Motor

Glow

Plug

Motor

Glow

Plug

MotorMotor

GlowGlow

PlugPlug

Motor

Glow

Plug

Motor

Glow

Plug

MotorMotor

GlowGlow

PlugPlug

Motor

Glow

Plug

Motor

Glow

Plug

Using the EZ-Start

Your EZ-Start controller plugs into a 4-prong receptacle in the center of
the pickup bed on your Revo. When the red button on the controller is
pressed, the EZ-Start motor begins to spin the engine and power from
the control unit heats the glow plug. Assuming all settings and
preparations are correct, the engine should start almost immediately.

Each of the two status indicator LEDs on
the hand-held control unit, the Motor
LED and the Glow Plug LED, should
light green while starting. If either LED
fails to light while starting, there is a
fault indicated with that function:

If the Glow Plug LED fails to light,
the glow plug may be bad, or the
glow plug wire may be damaged or
disconnected.

Motor LED fails to light and the

If the
starter fails to operate, then the

EZ-Start is in protection mode.

Protection Mode

The EZ-Start uses Smart Start™technology to monitor the condition of
the system and detect failures. The controller monitors the load being
placed on the EZ-Start motor. If the load becomes excessive, the system
shuts off power to the motor to prevent costly damage to the motor and
the controller. This may occur, for example, if the engine floods with fuel
during starting. The starter spins at first but when excessive fuel in the
combustion chamber begins to lock up the engine, the starter motor
slows under the heavier load. This causes the protection circuit to shut
off the power to the motor. Allow at least 3 minutes for the starter motor
to cool and the circuit to automatically reset before continuing. Use the
time to find and eliminate the condition that caused the excessive load
on the starter motor.

Shutting Off The Engine

Turning off the switch for the radio will
not shut off the engine. To shut off the
engine, use the shut-off clamp on the
fuel line. Simply squeeze the clamp
closed to shut off the fuel supply to the
engine. Don’t forget to release it when
you restart the engine.

Avoid shutting off the engine by placing your finger over the exhaust
outlet, especially if you are through driving for the day. This will leave
more unburned fuel in the engine that could lead to harmful corrosion.

Always be careful not to touch the metal exhaust pipe after running, it
can become very hot.

Clearing a Flooded Engine

If the engine is primed for too long during startup, then it can
become flooded with fuel. When the engine is flooded it will no
longer turn due to excess fuel in the combustion chamber preventing
upward movement of the piston. Use the following procedure to clear
a flooded engine.

1. Remove the blue glow plug wire.

2. Remove the glow plug and gasket with the glow plug wrench

supplied with your model. A 5/16 nut driver will also work.

3. Turn the model upside down and plug in the EZ-Start controller.

4. Push the EZ-Start button for several seconds to clear the engine of

excess fuel.

5. Turn the model over and reinstall the glow plug and gasket.

6. Reconnect the blue glow plug wire to the glow plug.

7. Reconnect the EZ-Start controller

8. Do not prime the engine. Pull the throttle to 1/2 throttle and push the

EZ-Start button. The engine should start immediately.

When the EZ-Start
controller is in protection
mode, wait at least three
minutes before attempting
to start the engine, to give
the starter motor time
to cool.

It’s normal for your EZ-Start
controller to become warm
after repeated use.

Revo •27

The TRX 2.5R Racing Engine

See Important Points to
Remember on page 4 for
other precautions.

Never run your Revo
indoors. Since the TRX 2.5R
Racing Engine exhaust
fumes are harmful, always
run your Revo outdoors, in
a well-ventilated area.

Your TRX 2.5R Racing
Engine doesn’t usually
require priming. If you do
need to prime your engine,
watch the fuel line carefully
to avoid flooding your
engine. See page 27 for
information on clearing a
flooded engine.

Factory Needle Settings

Your carburetor is preset at
the factory to give the
correct air-to-fuel ratio and
idle speed for engine break­in. Do not adjust the
carburetor unless you
observe a poor running
condition that requires
correction (see page 25 for
stock settings).

28•Revo

Breaking in Your TRX 2.5R Racing Engine

The TRX 2.5R Racing Engine uses a ringless, aluminum-brass-chrome (ABC)
piston/sleeve construction. This type of engine design relies on a very
precise running fit between the piston and sleeve for cylinder sealing.

Engine break-in is necessary to allow the piston and sleeve to develop
an extremely precise fit and optimum cylinder sealing. Therefore,
proper engine break-in is critical to achieving the fastest, most reliable
engine performance.

Allow yourself about 1 to 1
The engine break-in period will take 5 tanks of fuel in a Revo. The break-in
time is not the time to impress your friends with your new Revo. You must

wait until the engine is fully broken in before attempting sustained high
speed running. Patience and careful attention during break-in will reward

you with the best-performing TRX 2.5R Racing Engine possible.

During break-in, your engine may appear to malfunction with symptoms
like stalling, inconsistent performance, and
simply the normal “break-in pains” engines sometimes go through. They
will disappear once your engine is fully broken in. Many owners report not
experiencing any of these symptoms with the TRX 2.5R Racing Engine. We

recommend to go ahead and replace the glow plug with a new one
after the engine break in procedure.

Engine Break-in Procedure

The focus during break-in is to vary and limit the engine speed. This will be
accomplished by accelerating and stopping at different rates for the first 5
tanks of fuel. As the engine begins to break-in, the duration and intensity
of the acceleration will gradually increase. Sustained high-speed running
is not permitted until the 6th tank of fuel. Perform the initial break-in on
a large, flat, paved surface. Apply all throttle and braking actions gently.

Abrupt acceleration or braking could cause the engine to stall
unnecessarily.

Special break-in fuels are not recommended. Use the same fuel you
plan to use everyday.
If possible, avoid breaking-in the engine on extremely hot or cold days
(see page 32).
Pay careful attention to the fuel level. Do not allow the fuel tank to run
completely empty. An extremely low fuel level causes the mixture to
run too lean. This could result in a burned glow plug or extremely high
engine temperatures.

1

/2hours to complete the break-in procedure.

glow plugs. These are

fouled

Do not attempt to break in the TRX 2.5R Racing Engine by idling it on a
stand. This will produce poor results.
Keep extra Traxxas glow plugs (part #3231 or 3232) handy. The break-in
process can cause deposits to form on the plug leading to plug failure.
Change or clean your air filter after break-in.
Follow the instructions exactly for each of the first 5 tanks of fuel.

Starting Your TRX 2.5R Racing Engine for the First Time

Before you start your TRX 2.5R Racing Engine for the first time, make sure
you have read all instructions and precautions in this manual. Pay close

attention to the tank-by-tank break-in instructions in the next section,
and make sure you have read and understood them before you run
your engine.

Your engine must be at room temperature (70°F or 21° C) or above the
first time you start it. If it’s cooler than room temperature outside, keep

your Revo indoors until you’re ready to start it and then take it outside. If
it’s colder than 45 degrees, special considerations should be made. See
cold weather break-in on page 32. We do not recommend running the
model in temperatures below 35 degrees.

1. Turn on the radio system (see page 16).

2. Make sure the throttle trigger on the

transmitter is in the idle (neutral) position.

3. Connect the EZ-Start controller according to

the instructions on page 27.

4. Press the starter button in short two second

bursts and watch for fuel moving through the
fuel line up to the carburetor. Watch closely!
The fuel moves very fast. If the fuel doesn’t move through the line
within 5 seconds, prime the engine by briefly (one or two seconds)
covering the exhaust outlet with your finger until the fuel is just visible
in the carburetor fuel line. Watch carefully! If the engine is primed too

long, it will flood with fuel and stop turning.

5. Once fuel reaches the carburetor, the engine should quickly

start and idle.

6. Disconnect the EZ-Start controller from the model.

7. Proceed with the engine break-in.

8. Do not rev your engine with no load (wheels off the ground).

If your engine doesn’t start, refer to the TRX 2.5R Racing Engine
troubleshooting
contact Traxxas Customer Support

section at www.Traxxas.com. If you still have problems,

at 1-888-TRAXXAS.

The TRX 2.5R Racing Engine

Tank 1

1. Drive the model with the body off.

2. Driving procedure: Gently pull the throttle trigger to 1/4 throttle
over a 2-second count. Then gently apply the brake to stop. Count

the two seconds out while accelerating: one thousand one, one
thousand two, and then stop. Operate the throttle trigger as
smoothly as you can. Repeat this starting and stopping procedure

until the first tank of fuel is nearly empty.

3. Look for thick blue smoke exiting the exhaust outlet. If there is no

smoke, richen the high-speed needle 1/4 turn, by turning the needle
counterclockwise.

4. When the fuel tank is nearly empty, shut off the engine by pinching
the fuel line connected to the carburetor (use the installed clamp).

5. Let the engine cool for 15 minutes.

Note: If at any point the engine cuts out or stalls during gentle
acceleration, richen the high-speed needle 1/4 turn by turning the
needle counterclockwise.

Tank 2

1. From tank 2 forward, Revo should be driven with the body on.

2. Driving procedure: Gently pull the throttle trigger to 1/2 throttle
over a 2-second count. Then gently apply the brake to stop. Count

the two seconds out while accelerating: one thousand one, one
thousand two, and then stop. Repeat this starting and stopping

procedure until the second tank of fuel is nearly empty.

3. When the fuel tank is nearly empty, shut off the engine and let it cool

for 15 minutes.

Tank 3

1. Driving procedure: Gently pull the throttle trigger to 1/2 throttle
over a 3-second count. Then gently apply the brake to stop. Count

the three seconds out while accelerating: one thousand one, one
thousand two, one thousand three, and then stop. Repeat this

starting and stopping procedure until the third tank of fuel is
nearly empty.

Tank

1
2
3
4
5

Throttle

1/4
1/2
1/2
Full
Full

Time

2 Seconds
2 Seconds
3 Seconds
3 Seconds
5 Seconds

Cool

15 Minutes
15 Minutes

-

-

-

2. As the engine loosens, the idle speed may increase and cause the

model to try to creep forward when stopped. Reduce the idle speed
by turning the idle adjustment (see page 19) on the carburetor
counterclockwise.

3. When the fuel tank is nearly empty, shut off the engine and refuel.

From here on, you do not need to let the engine cool between tanks.

Tank 4

1. Driving procedure: Gently pull the throttle trigger to full throttle
over a 3-second count. Then gently apply the brake to stop. Count

the three seconds out while accelerating: one thousand one, one
thousand two, one thousand three, and then stop. Repeat this

starting and stopping procedure until the fourth tank of fuel is
nearly empty.

2. Apply the throttle gradually! Your finger should not reach full throttle

until the end of the three-second count. Revo may try to shift into
second gear. If it does, reduce the throttle input. Do not let Revo shift
out of first gear.

3. Keep your driving smooth and consistent.

4. When the fuel tank is nearly empty, shut off the engine and refuel.

Tank 5

1. Driving procedure: Gently pull the throttle trigger to full throttle
over a 3-second count, hold for 2 more seconds, and then gently
apply the brake to stop. Count the five seconds out while
accelerating. Repeat this starting and stopping procedure until the
fifth tank of fuel is nearly empty.

2. The model should now be shifting into second gear. If it is not, try

turning the high-speed needle clockwise 1/8 turn to lean the fuel
mixture slightly and test for shifting.

3. When the fuel tank is nearly empty, shut off the engine and refuel.

Tank 6

STOP! Clean your air filter before you proceed. Refer to the instructions

on page 23. During the sixth tank of fuel, the engine can be tuned for
general performance use. Proceed to the next section in this manual.

Body

Off
On
On
On
On

Notes

Apply throttle gradually.
Apply throttle gradually.
Reduce idle speed if necessary.
Do not allow shifting to high gear.
Accelerate over 3 second count, hold for 2 seconds.

High Altitude Operation:
If you live in a high altitude
region (5000 or more feet
above sea level), the lower
air density may require you
to lean your high-speed
fuel mixture slightly from
the factory break in
settings. Try this if you are
experiencing difficult
starting or extremely
sluggish engine
performance at high
altitude.

As you gain experience in
the hobby, you may
discover that many people
have differing opinions on
what is the proper
procedure to break-in a
model engine. Only use the

Traxxas break-in procedure.
Other break-in procedures
could result in a weak,
damaged, or otherwise poor
performing engine. The

procedure outlined here
was extensively tested and
proven to yield better
performing engines than
other “common” break-in
methods. Even if you have
years of experience using
model engines, please do
not ignore this caution!

Revo •29

The TRX 2.5R Racing Engine

When tuning for
performance, watch closely
to notice when there is no
longer any increase in speed
or power when the
high-speed mixture is lean.
If you lean the high-speed
mixture to the point that the
engine cuts-out, hesitates,
or stalls, you are well into
the danger zone and engine
damage is likely. Richen the
high-speed needle 1/4 turn
and retune.

For your convenience, the
low-speed needle has a
positive stop that prevents
it from being over tightened
and damaging the needle
and seat. This also provides
an easy way to gauge how
many turns out from closed
the low-speed needle
adjustment is set to.

Tuning Your TRX 2.5R Racing Engine

The engine’s performance depends on the fuel mixture. Turn the mixture
needles clockwise to lean the fuel mixture and counterclockwise to
richen it. Leaning the fuel mixture will increase engine power up to the
engine’s mechanical limits. Never run the engine too lean (not enough

fuel flow). Never lean the engine until it begins to cut-out or stall.

Leaning the engine beyond the safe allowable limits will result in poor
performance and almost certain engine damage. Indications of an

overly lean mixture include:

Cutting out or sudden loss of power during acceleration.

Overheating (temperature beyond 270° F at the glow plug)
Little or no blue smoke coming from the exhaust.

If any of these conditions are present, stop immediately and richen the
high speed mixture 1/4 turn. The engine will probably be slightly rich at
that setting and you can then retune for performance. Always tune for
performance by starting rich and moving leaner toward the ideal setting.
Never try to tune from the lean side. There should always be a light
stream of blue smoke coming from the exhaust.

Before you begin tuning, the engine should be warmed up to its normal
operating temperature and running slightly rich. All final tuning
adjustments must be made to the engine at its normal operating
temperature. You can tell the engine is running rich by noting any of the
following:

Sluggish
the exhaust.
Revo may not shift into second gear
There is unburned fuel spraying from the exhaust tip
Leaning the high-speed fuel mixture increases performance

acceleration with blue smoke coming from

or loss of control. Continue this procedure until there is no longer any

per

formance improvement.If any one of the following conditions occurs,

the fuel mixture is already past the maximum safe lean setting:

1. There is no longer any performance improvement

2. The engine begins to cut out at high speed (Danger!)

3. There is a sudden loss of power during acceleration (Danger!)

4. The engine begins to overheat. Symptoms of overheating include:

Steam or smoke coming from the engine (not exhaust)
Hesitation or stalling
Popping or clattering sound when decelerating (detonation)
Fluctuating idle speed
Temperature measurement above 270° F at the glow plug

Richen the fuel mixture to the optimum setting by richening the high­speed needle at least 1/8 turn counterclockwise and retest. This setting
will extend engine component life.

during acceleration

30•Revo

High-Speed Fuel Mixture Adjustment

With the engine warm and running at a rich setting, gradually lean the
high-speed fuel mixture in 1/16 turn increments. Make several high-
speed passes with Revo after each adjustment to clear out the engine
and note any change in performance. The TRX 2.5R is extremely
powerful. Remember to apply the throttle gradually to prevent wheelies

The TRX 2.5R Racing Engine

Low-Speed Fuel Mixture Adjustment

The low-speed mixture is always set after the high-speed needle is
correctly adjusted. The low-speed mixture is set using the pinch test.

1. Once the engine is warm, do several high-speed runs to confirm that

the high-speed needle is set correctly.

2. Bring the vehicle in and pinch closed the fuel line going into the

carburetor (use the engine shut-off clamp). The engine should run
for 2-3 seconds, speed up, and then shut off.

3. If the engine runs longer than 3 seconds, then lean the low-speed

needle 1/16 turn, make several more high-speed runs, and retest.

4. If the engine shuts off immediately without speeding up, then richen

the low-speed needle 1/8 turn, make several more high-speed runs,
and retest.

When the low-speed needle is set correctly, the engine’s throttle
response should be very quick, possibly even to the point of making it
difficult to keep Revo from doing a wheelie when you accelerate!

Idle Speed Adjustment

Once the high and low-speed mixtures have been set, reduce the idle
speed to the minimum reliable idle speed. Remember, this adjustment
should be made while the engine is running at normal operating
temperature.

1. Turn the throttle trim on the transmitter so that the brakes are

applied (note its original position). This ensures that the throttle slide
is resting against the idle adjustment screw.

2. Turn the screw counterclockwise to reduce the idle speed, or

clockwise to increase it. The idle speed should be set as low as
possible while still maintaining reliable running characteristics.

3. Reset the throttle trim on the transmitter to its original position.

Fine-Tuning the Carburetor

After fine-tuning your TRX 2.5R Racing Engine at the end of the break-in
procedure, no major adjustments to the fuel mixture are usually
necessary. Make note of the temperature, humidity, and barometric
pressure at the time you finished fine tuning your carburetor. Current
weather conditions can be found online from national websites, local TV
news websites, and television. This information will be considered your
baseline setting.

You may need to adjust your carburetor needles to compensate for
changes in temperature and barometric pressure (air density) from day
to day. Generally, you’ll need to richen the fuel mixture when the
weather is colder than your baseline temperature and the air density is
higher. Lean the fuel mixture when weather is warmer than your
baseline temperature and the air density is lower. The chart below
provides general guidelines on how weather conditions affect air density
when they move higher or lower than your baseline setting (see page 24
for detailed info on how air density affects mixture settings).

When adjusting the low
speed fuel mixture, it is very
important to make several
high-speed runs with Revo
between adjustments to
clear out any excess fuel.
Perform the pinch test
immediately after. If the
engine is allowed to idle for
a long period of time, it
could “load up” with fuel
and give you an inaccurate
measurement from your
pinch test.

If the...

Humidity

Pressure (barometer)

Temperature

Altitude

Nitro %

is..

Lower
Higher
Lower
Higher
Lower
Higher
Lower
Higher
Lower
Higher

then the

air density is...

Slightly more dense
Slightly less dense

Less dense
More dense
More dense
Less dense
More dense
Less dense

adjust (correct)

the fuel mixture to be...

Slightly richer
Slightly leaner

Leaner
Richer
Richer
Leaner
Richer
Leaner
Leaner
Richer

Revo •31

The TRX 2.5R Racing Engine

Winter Break-in Tips

During the break-in process, the piston and sleeve wear into each other to
form a precise fit. The engine needs to heat up to a temperature around
200 to 215 degrees to allow the piston and sleeve to achieve this fit
properly. A precise fit between these two components is critical for proper
compression, and optimum performance. If the engine runs too cold during
break-in, the piston and sleeve will not expand to their appropriate sizes for
break-in, and this can lead to premature wear of these components. This
wear may not become apparent until after winter has past, and the engine
is operated under warmer running conditions.

Warm the engine to approximately room temperature with a heat gun,
or keep the vehicle inside at room temperature just before starting the
engine. The engine can become difficult to start in cold weather.

After the engine is running, it is important to keep the temperature of
the engine up around 200 to 215 degrees during break-in. In weather
below 45 degrees, the TRX 2.5R Racing Engine will tend to run at lower
temperatures between 160 to 180 degrees (when tuned at proper
break-in mixture settings). This is too cool for break-in. Do not lean the
engine to increase engine temperature! This will also decrease
lubrication and cause your piston/sleeve to wear prematurely.

Wrap the cooling head with a paper
towel, clean rag or sock to help keep the
engine running around the
recommended 200 to 215 break-in temp.
If too much heat is contained, the engine
can actually run too hot. Make sure that
you monitor the engine's temp closely for
the first couple of tanks until you get the
right amount of cover for the cooling
head. This will, of course, depend on your current weather conditions.
Adjusting the cover up and down, exposing more or fewer cooling fins,
is a convenient way to regulate engine temps.

For owners that do not have access to a temperature probe, a drop of
water on the cooling head (around the glow plug area) should slowly
sizzle for approximately 6 to 8 seconds around 200 to 210 degrees. If the
water sizzles for only a few seconds, then it is likely that it is over 220
degrees, and needs to cool down. If the water takes a long time or does
not evaporate at all, then the engine is too cool.

We do not recommend that you operate your engine below 35 degrees
Fahrenheit. If you insist on running your vehicle below 35 degrees, just
make sure you are aware that nitro engines may be very difficult to start
and tune at those extremely cold temperatures. Also, at temperatures
below freezing, nitro fuel can actually begin to gel up, and this can be
harmful to the engine.

Follow the remaining break-in procedures as outlined in this owner's
manual. This, along with the steps listed above, will ensure a good break-in
for your new nitro engine, and provide many hours of enjoyment.

Tuning the Engine by Temperature

The following procedures require an
optional infrared temperature probe or
on-board temperature gauge (Traxxas
on-board digital temperature gauge, part
#4090 or #4091). Engine temperature can
be used as an effective tuning aid when you
understand the relationship between engine temperature and ambient
temperature. The engine operating temperature, when tuned for maximum
performance, will vary according to atmospheric conditions. The
atmospheric condition that has the most influence on engine temperature
is air temperature. Expect the engine temperature to vary almost in direct
proportion to air temperature. Assuming you tuned the engine for the
same maximum performance each day, the engine will run about twenty
degrees hotter when it’s ninety degrees outside than it would in seventy­degree weather. For this reason, we cannot give you a definitive
temperature range that indicates the best possible engine tuning.
The temperature gauge can aid you in tuning by giving you a relative
indication of how your adjustments are affecting the engine and by
preventing you from exceeding maximum engine temperature. For
example, as you lean the fuel mixture, the engine performance will increase
along with the temperature. If you continue to lean the fuel mixture and
the temperature increases but the engine performance does not change,
then you have exceeded the maximum safe lean setting.
Even if it’s 100°F outside, you should be able to tune for maximum
performance. Try to keep your engine from exceeding 270°F when
measured at the glow plug. If tuning for maximum performance results in
engine temperature exceeding 270°F, try to increase airflow to the engine
by cutting out the rear of the body, windshield, and front valance. If the
engine temperature still cannot be kept below 270°F, richen the high-speed
needle slightly.

32 •Revo

Driving Your Revo

SHIFT

REVERSE

SHIFT

FORWARD

Introduction

Your TRX 2.5R Racing Engine is broken in, the fuel mixture is balanced,
and the idle is set…now it’s time to have some fun! This section contains
instructions on forward/reverse shifting, and making adjustments to
your Revo. Before you go on, here are some important precautions to
keep in mind.

Don’t run your Revo in water, mud, snow, or wet grass. It’s
tempting, but water and mud are easily drawn through the air filter

and will severely damage the engine. Small amounts of moisture
cause electronics to fail and loss of control over your Revo.

The TRX 2.5R Racing Engine is extremely powerful. Remember to
apply the throttle gradually to prevent wheelies

Don’t hold Revo off the ground and rev the engine excessively with
no load on the engine. This practice could result in internal engine
damage. Avoid over revving the engine when Revo is airborne after
a jump.

Avoid excessive high-speed running for extended periods of time or
over long distances. This could cause the engine to build up enough
speed to exceed maximum safe RPM limits.

Don’t drive your Revo with drive train damage of any kind. The
engine could be damaged due to overloads caused by drivetrain
friction, or over-revving caused by loose or missing parts.

Don’t tow anything with your Revo. The engine is cooled by airflow
created by speed. Towing creates a high load on the engine, and at
the same time limits cooling of the engine due to low vehicle speed.

If your Revo gets stuck, stop driving immediately. Move the vehicle
and then continue driving.

Never turn off the radio system while the engine is running. The truck
could run out of control.

or loss of control.

can

Forward and Reverse Operation

Forward and reverse gears are
selected with the shift button
located in the transmitter handle
grip. The switch is normally in the
down, or forward, position.

To shift into reverse, bring your
Revo to a complete stop and
push the shift button up.
Accelerate to engage the gear.

To return to forward gear, repeat the same procedure and move the
shift button down.

Revo will not shift between forward and reverse unless the truck is
stopped. If it will not shift, then refer to the troubleshooting section
on www.Traxxas.com or call Traxxas support.

Driving Tips

Monster trucks by design have a high center of gravity that requires a
different driving technique. To prevent rollovers, slow down as you
approach turns and then apply moderate throttle through the turns.
This technique will help Revo grab the surface and turn sharper.

Do not apply brakes and turn the wheel at the same time. You could
tip the truck over.

When jumping, apply some throttle while Revo is in the air to keep
the truck’s nose up and land level on all 4 wheels. Be careful not to
over-rev the engine or land at full throttle. Either could seriously
damage your Revo. If the nose of the truck is too high, then quickly
tap the brake to level the truck in the air.

Drive over large obstacles (such as curbs and rocks) at an angle,
instead of head on. This will allow the suspension to articulate and
absorb the impact much easier.

Even though Revo is capable of high speed in reverse, it is very
difficult to control while driving in reverse. Limit your reverse speed
to prevent crashing or flipping your Revo.

Change or clean your air filter element after each hour of running.
This is critical for the life of your engine. Running time includes the
engine break-in period.

Revo •33

Basic Tuning Adjustments

Compression 2/3

Sag (Droop) 1/3

Ride Height

Tot al Travel

Axle Centerline at Ride Height

Axle Centerline at Max Compression

Axle Centerline at Max Sag

34 •Revo

This tuning and setup guide is separated into two sections- Basic and
Advanced. Revo does not require any specialized knowledge or
understanding of its unique suspension and drive train to perform
typical, everyday setup and track tuning adjustments. Adjustment
procedures for alignment, spring rate, damping, steering, and ride
height are covered in the basic tuning section. Adjustments for the gear
ratio, 2-speed shift point, slipper clutch, and brake are also covered. In
most cases, the basic information is all that is needed to tune Revo to
perform well on a variety of surfaces.

Revo was engineered to provide sophisticated additional tuning options
well beyond the basics that allow expert users to extract the maximum
performance from the truck. The advanced tuning section (beginning on
page 42) covers topics such as optional suspension rockers, roll center
adjustment, caster adjustment, bump steer tuning, differential setup,
and fine tuning the 2-speed gear ratios. Make sure you fully understand
the basic adjustments before experimenting with the advanced
adjustments. Improper combinations of adjustments can adversely affect
the performance of the truck, resulting in poor handling. If you don’t
know why you are changing an adjustment then you should leave it at
its factory setting. Also included are instructions for using the Long­Travel rockers and springs supplied with Revo. The long travel rockers
allow extreme suspension travel for rock crawling and rough, large-scale
terrain. The long travel rockers allow the suspension to operate at its
extreme mechanical limits and is recommended for advanced users.

Suspension Tuning

Springs

The front and rear springs on Revo have different spring rates. The
rear springs are about 20% stiffer than the front springs. The spring’s
pre-load tension can be adjusted by turning the spring pre-load adjuster.
Adjusting the pre-load changes the suspension sag. Suspension sag
basically defines how much the suspension compresses when the truck
is at rest. Adjust the pre-load so that the suspension compresses about
one third of its full suspension travel (see illustration). If suspension sag is
severe and requires a large increase of the spring pre-load to
compensate, then a firmer spring should be used. Firmer springs
(supplied) must be used when the Long Travel rocker arms are installed.

Use a stiffer spring to reduce sag, reduce body lean, control brake dive,
and provide a firmer, more responsive overall feel. If Revo is lightened
significantly for racing applications, softer springs will be necessary to

allow the suspension to
sag properly. Heavier
configurations will require
stiffer springs. Ride height
is adjusted by changing
the length or position of
the pushrods in the lower
suspension arms. See the
next section for ride
height adjustments. The
suspension sag and spring
pre-load should be
readjusted anytime the
springs are removed and/or replaced.

Optional springs available from Traxxas are listed below. Refer to your
parts list for a complete part number listing. Higher rate springs are
stiffer. Springs can be identified by dots of color on one end.

90mm Travel

Dot Color Spring Rate

Yellow 14.8 lb/in (2.6 N/mm)
White 16.6 lb/in (2.9 N/mm)

(Standard Front)

Orange 18.3 lb/in (3.2 N/mm)
Green 20.0 lb/in (3.5 N/mm)

(Standard Rear)

Gold 21.7 lb/in (3.8 N/mm)
Tan 23.4 lb/in (4.1 N/mm)
Black 25.1 lb/in (4.4 N/mm)

120mm Long Travel

Dot Color Spring Rate

Silver 28.0

(Standard Front)

Pink 30.8 lb/in (5.4 N/mm)
Blue 33.7 lb/in (5.9 N/mm)

(Standard Rear)

Purple 36.5 lb/in (6.4 N/mm)

Note: 90mm Travel springs are

not recommended for use with
the Long Travel Rockers.

lb/in (4.9 N/mm)

Ride Height Adjustment

The rocker arm suspension uses push rods on each suspension arm.
Changing the length and/or position of the push rod adjusts the ride
height without affecting or compromising other suspension parameters.
For example, you can raise and lower the ride height without changing
up/down travel distribution, changing springs, or affecting your
progressive rate. This feature is unique to Revo and is extremely
beneficial in a racing environment where you can achieve a low center of
gravity (by lowering the ride height) without losing any suspension
capability. Increasing the ride height will increase ground clearance for
rough terrain.

Basic Tuning Adjustments

The ride height of the model
can be changed by mounting
the push rod in a different hole
in the lower suspension arm.
From the factory, the push rod
comes installed in the center
hole of the lower suspension
arm’s push rod mount. If the

Increases

Ride Height

Decreases

Ride Height

push rod is mounted in the inner hole, the ride height of the vehicle
increases. If mounted in the outer hole, the ride height decreases.

The ride height can be finely tuned by adjusting the sag of the
suspension. Do not attempt to make large changes to the ride height
by adjusting the spring pre-load on the shock bodies. If suspension sag
is severe and requires a large increase of the spring pre-load to
compensate, then a firmer spring should be used. The lowest ride height
can be achieved by installing the optional adjustable push rod in the
outermost hole of the lower suspension arm’s push rod mount. Turn the
rod ends all the way in until they stop (shortening the length).

The optional Long Travel rocker arms are designed to be used only with
the standard non-adjustable push rods installed in the hole labeled “LT”
(the middle hole of the lower suspension arm’s push rod mount). Any
minor adjustments to the ride height are accomplished by adjusting the
spring pre-load.

Adjusting the Pivot Ball Caps

The pivot ball caps should be
adjusted so that the pivot balls
operate freely in the axle carriers with
no excess play. Use the provided four­way suspension multi-tool to tighten
or loosen the pivot ball cap.

Shock Oil

The 4 oil-filled aluminum shocks (dampers) effectively control the
suspension movement by preventing the wheels and tires from
continuing to “bounce” after rebounding from a bump. Changing the oil
in the shocks can vary the suspension damping effect. Changing the oil to
a higher viscosity oil will increase damping. Lowering the viscosity of the
oil will cause the suspension damping to be reduced. Damping should be
increased (with higher viscosity oil) if the model is bottoming easily over
jumps. Damping should be decreased (with thinner viscosity oil) if the

model is hopping over small bumps and feels unstable. The viscosity
of shock oil is affected by extremes in operating temperature; an oil of
certain viscosity will become less viscous at higher temperatures and
more viscous at lower temperatures. Operating in regions with cold
temperatures may require lower viscosity oil. From the factory, the shocks
are filled with SAE-30W silicone oil. Only use 100% silicone oil in the shock.

For shock piston tuning see Advanced Tuning Adjustments on page 44.

Replacing Shock Oil

The shocks have to be removed
from the vehicle and disassembled
to change the oil.

1. Remove the lower spring

retainer and shock spring.

2. Remove the upper shock cap

using the shock wrench and the
suspension multi tool

3. Empty the used shock oil from the shock body.

4. Fill the shock with new silicone shock oil up to the top of the

shock body.

5. Slowly move the piston up and down (always keeping it submerged in

oil) to release the air bubbles. Let the shock sit for a few minutes to
allow any remaining air bubbles to surface.

6. Slowly thread the upper cap with the installed shock bladder onto the

shock body with the suspension multi tool. The excess oil will bleed
out of the small hole in the shock cap.

7. Tighten the shock cap until snug. Use the included steel shock wrench

to hold onto shock body while tightening.

Important: The shocks are
assembled at the factory
with a center-to-center
distance (between the
rod end balls) of 87mm.
Any time the shocks are
removed and disassembled,
this distance should be
checked to ensure
proper operation of
the suspension.

87mm

Revo •35

Basic Tuning Adjustments

Front of Truck

Front of Truck

Left Front

Right Front

Left Hand Thread

Indicator

Left Hand Thread

Indicator

For caster, roll center, and
optional rocker arm tuning
see Advanced Tuning
Adjustments on page 42.

A camber gauge (available
at your local hobby shop)
can be a useful tool for
alignment setting.

All of the toe links are
installed on the truck so that
the left hand thread
indicators point to the same
direction. This makes it easier
to remember which way to
turn the wrench to increase
or decrease toe link length
(the direction is same at all
four corners). Note that the
groove in the hex indicates
the side of the toe link with
the left-hand threads.

Alignment Settings

The alignment settings are critical for optimizing the performance of Revo.
Adjust your alignment as carefully and precisely as you possibly can.

Toe Adjustment

The wheels can be adjusted to point
straight ahead or have a toe-in or
toe-out setting. To help you
remember, look down at your feet.
For toe-in, your feet point towards
each other. For toe-out, your feet
point away from each other.

The toe angle of the front wheels can
be adjusted by varying the length of
the toe links that connect the
steering linkage to the front axle
carriers. The toe angle of the rear
wheels can be adjusted by varying
the length of the metal toe links that
connect the rear bulkheads to the
rear axle carriers. The front toe links

Right Hand

(Normal) Threads

and rear toe links are equipped with
turnbuckles. The lengths of the toe
links can be adjusted by turning
them with the included 5mm Traxxas
wrench.

Left Hand

Threads

Decrease

Length

Toe Base Factory Settings
Front: 0-degrees
Rear: 1-degree toe-in each side

Under certain conditions, toe-in can be increased to a maximum of 3
degrees. To avoid potential interference of suspension components with
the long travel rockers installed, see the maximum alignment limits table
on page 37.

Increase

Length

Static Camber Adjustment

The wheels can be set to have either
positive or negative camber (see illustration
below). The camber angle changes as the
wheel moves up and down through its
range of travel. Static camber is the camber
angle at the wheel when the vehicle is set at
its normal, stationary ride height.

The suspension pivot balls located in the
axle carriers adjust the static camber. The
pivot balls are protected by blue dust plugs. To adjust your static camber,
insert the supplied 2.5 mm hex wrench through the slit in the dust plug
and engage the end of the pivot ball (compressing the suspension until
the arms are parallel to the ground will allow for easier hex wrench
engagement). The upper pivot ball is normally screwed all
the way in. Negative camber is achieved by screwing the pivot ball of the
lower control arm out. Note: When camber is changed, the toe angle of
the wheel has to be reset.

Static Camber Base Factory Settings
Front: 1-degree negative camber each side
Rear: 1-degree negative camber each side

Positive camber

Negative camber

36 •Revo

Basic Tuning Adjustments

Maximum Alignment Limits (using stock push rod length)

Revo’s maximum toe and camber alignment settings can be limited by
the ride height setting. Do not exceed the maximum limits or you could
experience interference between suspension components. The ride
height is controlled by where the push rod is installed in the lower
suspension arm. First determine which of the following configurations
you are using:

a. Stock Configuration – When the pushrod is in the middle position of the

lower control arm.

b. Raised Configuration - When the pushrod is in the raised position to

increase the vehicle’s ride height (innermost hole in lower control arm).

c. Lowered Configuration - When the pushrod is in the lowered

position to decrease the vehicle’s ride height (outermost hole in
lower control arm).

d. Long Travel Configuration – When the pushrod is in the middle

position of the lower control arm with the Long Travel rockers installed.

Front Suspension

The following are suggested maximum settings for the front suspension
in order to avoid interference between suspension components:

Available

Configuration

Stock

Raised

Lowered

Long travel

Rear Suspension

The following are suggested maximum settings for the rear suspension
for all configurations. Toe out is not normally used on the rear of Revo.

Configuration

All

Camber

(degrees)

+3 to -5
+3 to -1
+3 to -5
+3 to -1

Available

Camber

(degrees)

+3 to -5

Available Toe

(degrees)

Toe In

Toe In

Toe Out
3
1
3
1

Available Toe

(degrees)

Toe Out
3

3
1
3
1

2

Transmission Tuning

Adjusting the Slipper Clutch

Your Revo is equipped with an
adjustable Torque Control slipper
clutch. The slipper clutch is integrated
into the main spur gear on the
transmission (see page 6). The slipper
clutch is adjusted by loosening the
spring-loaded locknut on the slipper
shaft. Use the supplied 8mm open-end
metric wrench. To tighten or loosen the
slipper nut, insert the 2.0mm hex wrench into the hole in the end of the
slipper shaft. This locks the shaft for adjustments. Turn the adjustment
nut clockwise to tighten (less slippage) and counter-clockwise to loosen
(more slippage). The slipper clutch has two functions:

1. Limiting the engine’s torque output to the wheels to prevent

wheelspin on low traction surfaces and uncontrolled wheelies on
high traction surfaces.

2. Protecting the drivetrain from sudden impact or shock loads (such as

landing from a jump with the engine at full throttle).

From the factory the slipper clutch is set for minimal slippage, just
enough to protect the drivetrain from shock loads. On slippery, low
traction surfaces such as a hard-packed, dry racetrack you may benefit
from loosening the slipper adjustment nut to allow for more clutch
slippage. This will make the truck easier and more forgiving to drive by
helping to reduce the amount of wheel spin. Loosening the slipper
adjustment can also improve performance on extreme high traction
surfaces by preventing the front end from lifting off of the ground when
accelerating. Make slipper adjustments in small 1/8 turn increments.

The maximum tight setting for the slipper is just at the point where
there is little or no tire slippage on a high traction surface such as carpet
or a prepared racetrack. The slipper should not be tightened to the point
that clutch slippage is completely eliminated. Do not overtighten the
slipper nut or you could damage the slipper bearings, pressure plates, or
other components.

Revo •37

Basic Tuning Adjustments

Two Speed Adjustment
note: If the truck will not roll
forward while the spur gear
is held, the transmission
may still be in reverse gear.

For adjusting two-speed
and gear ratios see

Advanced Tuning
Adjustments on page 44.

38 •Revo

Adjusting the Two-Speed Transmission

Revo comes equipped with an adjustable two-speed transmission. When
the shift point on the transmission is adjusted correctly, it will maximize
acceleration and improve drivability. Use a 2mm hex wrench
to adjust the shift point. To make the adjustment, the engine must be off
(not running).

1. Shift the transmission into forward gear

(shift button down).

2. Remove the rubber access plug from the

top of the transmission housing.

3. While looking through the

opening, rotate the spur gear to
align the cutout (notch) on the internal
2-speed clutch drum with the opening.

4. Hold the spur gear and slowly roll the

truck forward until the hex on the black
adjustment set screw becomes visible in
the opening. Note: the truck will only roll
forward (not backwards) when the spur
gear is held stationary.

5. Insert the 2.0mm hex wrench

through the clutch drum and into
the adjustment screw.

6. Turn the adjustment screw 1/8 turn

counter clockwise to lower the shift
point (shifts sooner). Be careful not to
loosen the adjustment screw too much
or you may cause the screw and spring
to fall out (requiring major disassembly
and repair). Turn the adjustment screw
clockwise for later shifts.

7. Reinstall the rubber access plug to prevent dirt from entering the

transmission. Do not put oil or other lubricants into the transmission
through the two-speed adjustment access.

8. Check performance by running a test lap after each adjustment. On a

small race track with many tight turns, try setting the shift point later so
that the truck only shifts into second gear on the main straightaway. This
will prevent an unexpected shift in the middle of a turn. On larger tracks
it may be necessary to allow earlier shifts for increased speed.

Shift

Sooner

Adjusting the Spur Gear/Clutch Bell Gear Mesh

The ideal spur gear/clutch bell gear mesh for
Revo is 0.1mm. To set the gear mesh, place a
strip of standard letter/A4 size copy or printer
paper (about 0.1mm thick) between the
mating teeth. Loosen the two horizontal
engine mount screws and slide the engine
mount up to push the clutch bell gear against
the spur gear so that the that the paper is not
too tight to pull out or too loose that it will fall
out. Tighten the two horizontal engine mount
screws securely. When the paper is removed,
you should feel only the slightest amount of
play between the gears (almost none) and
there should be no binding or friction.

Changing the Spur Gear

1. Remove the four cap head screws that

secure the engine to the engine mount.

2. Remove the button head screw that

secures the pipe hanger to the rear body
mount (see inset).

3. Carefully remove the engine and exhaust

system from the spur gear area to allow enough
room to remove the spur gear.

4. Remove the three screws on the slipper clutch

assembly using a 2.5mm hex wrench. Slide the
spur gear off of the slipper shaft. If the spur gear is
too tight on the shaft, gently pry on the back of
the gear with a flat screw driver to loosen it.

Repeat the above steps in reverse order to install the new spur gear.

Dual Servo Steering System

Revo uses dual-servo steering and a single heavy-duty servo saver for
powerful, responsive steering. To prevent unnecessary receiver battery
drain it is important to make sure that the servos are “at rest” when the
steering is at neutral. If one servo is out of adjustment, then both servos
will work against each other, fighting to find center.

Adjusting The Steering System

1. Remove the servo horns and steering links from the servos. Disconnect

the steering links from the servo saver.

Basic Tuning Adjustments

2. Adjust both the steering links to be the exact same length (31.7mm - use

“Steering Servo Horn Link Length Template” on page 39 to set length).

3. Switch on the power to the receiver and the transmitter.

4. Adjust the steering trim on the transmitter to the neutral “0” position.

5. Connect one end of a steering link to the steering servo saver arm and

the other end to the servo horn

6. Position the steering servo saver arm

perpendicular to the centerline of the vehicle.

7. While holding the steering servo saver arm in

the position mentioned in step 6, install the
servo horn onto the servo such that the
steering link is parallel with the centerline of
the vehicle. This will automatically set the
servo horn at the
7-degree offset shown in the illustration.

8. Install the second servo horn on the other side

following the same procedure.

If necessary, fine-tune the length of the second steering link to eliminate
any load on the steering system in the neutral position.

If you are using aftermarket
servos, it is important to use
servo horns designed for Revo.
Optional steering servo horns
are sold separately for use with
non-Traxxas servos.

Steering Link Length Template

31.7mm

Servo Saver Tuning

An optional stiffer spring is available for the servo saver when using servos
with metal gear sets (see parts list for details). Do not use this spring with
standard Traxxas high-torque servos.

Brake Setup & Adjustment

Revo is equipped with a disc brake that rides on the yoke of the
transmission’s front output shaft. The brake is preset at the factory and
should not require attention. As the brake material wears, future
adjustments may be necessary.

material wears down. They should be tightened so a 0.50mm (.020") gap
exists between the disk and the brake pad (on the transmission side).
Adjust in one of the following ways:

1. Use a .50mm feeler gauge between

the brake pad insert and brake disk.

2. Push the outer brake pad firmly

against the inner pad with your
finger, sandwiching the brake disk
between the brake calipers. Tighten
the brake shoulder bolts until they just barely touch the brake pads. Do
not over tighten these fasteners or you could damage the brake calipers.
Loosen each of the shoulder bolts by 1 turn.

Brake Linkage Adjustment

When correctly adjusted, the brake linkage
spring should barely touch the rod guide
when the servo is in neutral position (closed
throttle). This will ensure no brake drag
during operation of the vehicle. The brake
adjustment knob can be threaded away from
the spring for less braking power if desired.
Do not adjust knob to apply pressure
against the spring while the servo is in the
neutral position. This will induce brake
drag and cause undesirable handling.

The position of the z-bend from the
factory is in the middle position of the
servo horn. Changing this position will
affect the way the brake force is applied.
The brake adjustment knob will need to be readjusted if this position
is changed.

Brake

Linkage

Spring

Front of Truck

.05mm

gap

Less Brake

Brake Pad Wear and Replacement

During normal use the brake pads should wear at a relatively slow rate.
However, if the brake pads wear down close to the metal pad holders, they
should be replaced. Any more wear than this could cause damage to the
brake parts and improper operation of the brake system.

Brake Shoulder Screw Adjustment

The two shoulder bolts that are used to secure the brake pads to the
transmission housing may need to be adjusted periodically as the brake

Revo •39

Maintaining and Storing Your Revo

If the engine is worn or
damaged enough to require
replacing the piston, sleeve,
or connecting rod, consider
exchanging your old engine
for a brand new engine
under the terms of the
Traxxas Lifetime Engine
Replacement Plan (ERP). It
could save you time and
effort. Details are in your
model’s documentation
package.

The TRX 2.5R Racing Engine
is designed to be easy to
rebuild. Critical engine
components such as the
crankcase, crankshaft, and
engine bearings are made
to extremely high quality
standards and should under
normal circumstances
outlast multiple sets of
pistons, sleeves, connecting
rods, and wrist pins
(reciprocating assemblies).
It could be more economical
for you to continue to use
your good bearings and
crankshafts, and simply
replace the reciprocating
assembly as needed. Engine
assembly is not difficult and
replacing the reciprocating
assembly does not require
any special tools or skills.

Your Revo requires timely maintenance in order to stay in top running
condition. Neglecting the maintenance could allow dirt, deposits, and

moisture to build up inside the engine leading to internal engine
failure. The following procedures should be taken very seriously.

After each hour of running:

Clean and re-oil the air filter. The instructions for this procedure are on
page 23. We cannot stress enough the value of cleaning your air
filter at the scheduled intervals. The cleanliness and condition of your
air filter directly influences the running life span of your engine. Do not

skip air filter maintenance!

Clean the outside of the engine of accumulated dirt, oil, and grime.
Accumulated grime will decrease the engine’s ability to cool itself.

After each running session:

Perform after-run maintenance on the engine. This clears the engine
of destructive moisture and other corrosive deposits. This is extremely

important for the life of the engine. See page 41 for after-run

maintenance procedures.

Inspect the gears for wear, broken teeth, or debris lodged
between the teeth

I

nspect the vehicle for obvious damage or wear. Look for:

1. Loose or missing screws

2. Cracked, bent, or damaged parts

3. Cut or loose wiring

4. Cut or kinked fuel lines

5. Signs of fuel leakage

Other periodic maintenance:

Connecting rod: The connecting rod should be replaced when the

piston and sleeve are replaced. Also replace the piston wrist pin and
G-clip whenever the connecting rod is replaced. As with other
internal engine components, connecting rod life depends engine’s
usage and the quality and frequency of the engine maintenance.
Inspect the connecting rod after 3-gallons of fuel have been used.

Slipper clutch pads (friction
material): Under normal use, the
friction material in the slipper
clutch should wear very slowly.
If the thickness of any one of the
slipper clutch pads is 1.8mm or less,
the friction disc should be replaced.
Measure the pad thickness using calipers or measuring against
the diameter of the 1.5 and 2.0mm hex wrenches provided with
the model.

Piston/sleeve: The life of the piston and sleeve will
vary greatly with how the engine was used and
maintained. The piston and sleeve should be
replaced when they no longer seal effectively (loss
of compression). Symptoms include the engine
being difficult to start when warm, stalling when
warm, and stalling when throttle is suddenly closed
to idle. Replace the wrist pin and G-clip whenever
the piston and sleeve are replaced.

40•Revo

After-run Procedure

You must perform after-run maintenance on your Traxxas engine
whenever the model will be stored for longer than a few hours. Taking
the time to prepare your engine for storage will reward you with longer
engine life, easier starting, and better performance.

When a nitro engine is shut off, some excess unburned fuel remains in
the engine. The methanol in model engine fuel is hygroscopic, which
means it easily attracts and absorbs moisture. This moisture can cause
rust and corrosion on the steel engine parts (crankshaft, bearings, wrist
pin and starter shaft) if the fuel is not removed from the engine. There are
after run oil products available from your hobby dealer or you can use
WD-40™, a common household lubricant. To ensure your TRX 2.5R Racing
Engine is protected from internal corrosion, use the following procedure:

1. Whenever possible, shut off the engine by pinching the fuel line

closed. This allows most of the excess fuel to be consumed by the
engine. Be sure the throttle is in the idle position. You may have to
pinch the fuel line closed for several seconds before the engine stops.

2. Completely empty the fuel tank. Use your fuel-dispensing bottle to

suck out the old fuel. Do not mix the old fuel with your fresh fuel
supply. If you leave fuel in the tank, transporting or handling your
Revo may cause fuel to run into the engine.

3. With the fuel tank empty and the throttle at the idle position, try to

start the engine. The engine will most likely start and run for a few
seconds as it uses up any fuel remaining in the engine and fuel lines.

Maintaining and Storing Your Revo

6. Place a rag or paper towel over the engine to catch any WD-40 or

after-run oil that may come out the carburetor or glow plug hole.

7. Connect the EZ-Start controller to the model and spin the engine for

10 seconds.

8. Remove the rag or paper towel and repeat steps 5–7 two more times.

9. Clean and re-oil the air filter so it will be ready for use next time. See

page 23 for air filter maintenance instructions.

10. Replace the glow plug, reconnect the glow plug power wire, and

reinstall the air filter.

Denatured alcohol
(available from home
centers and paint supply
stores) in a spray bottle is
an extremely effective
cleaner. Be sure to wear
safety glasses and gloves
when working with
denatured alcohol.

Be sure to follow proper
maintenance and storage
procedures to avoid
damage to your engine
and other components of
your Revo.

Don’t put the fuel from
your tank back into your
fuel jug. Dispose of it
properly, following city or
county regulations.

4. Once the engine stops, clean the outside of the engine with

compressed air or spray motor cleaner. Once the engine is clean and
dry, remove the glow plug power wire, glow plug, and air filter.

5. Open the throttle fully and spray a one-second burst of WD-40 into

the carburetor and into the glow plug hole (Caution! Wear safety
glasses to prevent spray from getting into your eyes). If you are using
after-run oil, follow the manufacturer’s instructions.

Always wear eye
protection when using
compressed air or spray
cleaners and lubricants.

Revo •41

Advanced Tuning adjustments

42 •Revo

This advanced tuning guide will take you one step further into the cutting
edge technology that has been designed into Revo. Follow the instructions
provided here to take advantage of Revo’s maximum performance
potential.

Suspension and Alignment Settings

Caster Adjustment

The caster angle of the front
suspension may be used to adjust the
understeer (push)/oversteer handling
characteristics of the model.
Generally, increasing the caster angle
will move the truck towards an
oversteer condition (more traction on
the front tires, less on the rear tires).
Decreasing the caster angle will
create a tendency towards understeer
(pushing in the turns). From the
factory, the front suspension is set to
a caster angle of 10-degrees. The rear
caster angle is not adjustable. The
caster angle of the front suspension can be adjusted from 5° to 15°. Adjust
the caster by positioning the caster adjustment shims on the upper control
arms of the front suspension as shown in the table below:

Number and Position of Caster

Adjustment Shims (Front Upper Control Arm)

In Front of

Caster

5.0°

7.5°

10.0°

12.5°

15.0°

Hinge Pin Boss

None

One
Two

Three

Four

Caster Angle, and Bump Steer

Bump steer is unwanted change in the steering angle of the front wheels
as the suspension travels up and down. It can result in unstable and
unpredictable handling. Bump steer is affected by the position of the outer
toe link end on the axle carrier. From the factory, the toe links are positioned
so that bump steer is virtually eliminated (about 3/100 of a degree through
the entire range of travel). When the caster angle is changed, the outer toe
link end should be repositioned on the axle carrier to maintain zero bump
steer geometry. Adjustment is achieved using the shims and hollow balls
provided with the vehicle. Refer to the Bump Steer Elimination chart on

Caster adjustment shims (2 front, 2 rear)

Vertical

10°

Ground plane

Behind

Hinge Pin Boss

Four

Three

Two
One

None

page 43, and look up your caster angle setting to find the correct position
for the outer toe links. Positioning the toe-links correctly will maintain the
original factory geometry and eliminate the unwanted steering angle
changes caused by bump steer.

Roll Center

There are two holes on the
bulkheads to mount each upper

Upper Control Arm

Upper Control Arm

Upper Mounting Holes

Upper Mounting Holes

suspension arm. The roll center of
the vehicle can be raised by
mounting the upper control arm in
the lower of the two holes. This will
effectively increase the roll stiffness

Upper Control Arm

Upper Control Arm

Lower Mounting Holes

Lower Mounting Holes

of the vehicle (similar to installing
swaybars). Adding roll resistance to
one end of the vehicle will tend to add traction to the opposite end. For
example, increasing roll resistance in the rear by installing the upper arms
in the lower holes will provide more traction for the front wheels and
potentially more steering. Installing the upper arms in the lower holes on
the front and rear will increase overall roll resistance without changing the
handling balance. The arms are installed in the upper position from the
factory to make the truck easier and more forgiving to drive and less likely
to traction roll in turns. The lower holes should be reserved for track tuning.
Note: When the upper suspension arms are moved to the lower holes, the
front outer toe link ends and the rear toe control links should be
repositioned to eliminate bump steer. Refer to the Bump Steer Elimination
chart on page 43, and look up your suspension combination (caster angle
and roll center position) to find the correct position for the front outer toe
links and the rear toe control links. Adjustment is achieved using the shims
and hollow balls provided with the vehicle.

Rockers (Progressive Rate/ Suspension Travel)

One of the most exciting aspects of Revo’s suspension is the inboard shock
(damper) arrangement that uses pivoting rockers to translate vertical wheel
travel into linear shock motion. The rockers can be changed to increase or
decrease the maximum wheel travel and also to change the progressive
rate of the suspension.

The progressive rate determines how much the force at the wheel
produced by the springs being compressed (wheel force) will vary with
suspension travel (or vertical travel of the wheel). On a progressive
suspension arrangement, the wheel force will increase at a faster and faster
rate as the suspension is compressed. It feels as though the shock spring
gets progressively stiffer the more you compress the suspension. On a
linear suspension arrangement, the wheel force increases linearly as the

Advanced Tuning Adjustments

Constant Rate Travel

Wheel Force

0

2

4

6

8

10

12

14

16

18

20

10 20 30 40 50 60 70 80 90

Progressive Rate Travel

suspension is compressed. The spring does not feel any stiffer, even when
the suspension is fully compressed. This provides a very “plush” feeling
suspension with seemingly bottomless suspension travel.

Rocker Arm

Progressive 1

Progressive 2

Progressive 3

Long Travel

(included)

A total of four different rocker arm sets are available for Revo. All rocker
arms except the Long Travel rocker arms will allow the wheel to travel a
total of 90mm in the vertical direction. From the ride height position, the
wheel will be able to travel 60mm in the upward direction (bump), and
30mm in the downward direction (droop). The Long Travel rocker arm
increases total travel to 120mm. The progressive rate can be increased or
decreased by installing different rocker arm sets. The rockers are labeled
Progressive 1 to Progressive 3. Progressive 1 rockers will provide a low
progressive rate that maintains consistent damping force across through
the whole range of suspension travel. These are best for extremely rough
terrain that requires maximum suspension articulation. Progressive 3
rockers use high progressive rate that will improve high-speed cornering
on smooth surfaces by providing a firmer feel. Body roll, brake dive and rear
squat will also be reduced. Always change all four rockers as a complete set.
Do not mix rates and travel.

Using rockers with lower progressive rate may require the use of stiffer
springs to maintain proper spring pre-load and ride height. The spring
pre-load adjuster on each shock is designed for minor adjustments. If the
adjuster needs to be turned all the way down (compressing the spring) in
order to maintain proper ride height, then the next stiffer spring should
be used.

The chart below demonstrate the effect of the various rocker arms on
wheel force as the suspension is compressed. On the progressive rate,
wheel force is light at first and increases as the suspension is compressed.

Total Travel

90mm

(60mm up/30mm down)

90mm

(60mm up/30mm down)

90mm

(60mm up/30mm down)

120mm

(80mm up/40mm down)

Progressive Rate

Low

Medium

High

Low

Bump Steer Elimination Chart

The illustrations and the following table detail the position of the outer toe
link end for various caster and roll center settings to eliminate bump steer.
The shims and the hollow balls used to adjust bump steer are provided
with your vehicle.

Front

Outer Toe Link End Setup

Standard
Hollow Ball

Thin Shim
Thick Shim

Thin Shim
Standard

Hollow Ball
Thick Shim

Tall Center
Hollow Ball

Thick Shim
Standard

Hollow Ball
Thin Shim

Thick Shim
Thin Shim
Standard

Hollow Ball

Caster

5° 7.5° 10° 12.5° 15°

Control Arm

Mounting Hole on

Front Bulkhead

Upper

Lower

Upper

Lower

Upper

Lower

Upper

Lower

Upper

Rear

When the rear upper control arms
are mounted in the lower of its two
mounting holes in the bulkhead (roll
center), the tall hollow ball should be
used as shown.

Tall Center

Hollow Ball

When using Long Travel
rockers, A correspondingly
thicker shock oil (or pistons
with smaller diameter
bypass holes) should also
be used to ensure a proper
relationship between the
spring and damping forces.

Revo •43

Advanced Tuning Adjustments

2

2

2

1

1

1

3

3

3

Shock Piston Hole Sizes

Piston 1: 1.10 mm

Piston 2: 1.00 mm

Piston 3: 0.95 mm

Never slide the threads on
the shock rod past the
X-ring seal when it is
installed and compressed
by the bottom cap of the
shock. Doing so will
damage the seal and cause
shock oil to leak.

44 •Revo

Shock Tuning

Multi-tool Shock Functions

Shock Pistons

The shock pistons can be replaced with
the available optional pistons to vary
the amount of damping. Optional
pistons with bypass holes that are
larger or smaller (1, 2, or 3) than the
factory installed stock pistons can be
used to decrease or increase damping
respectively. Change the pistons if you

A. Tighten/Loosen Upper Cap

only have one weight of shock oil
available to you. From the factory, Revo
is equipped with #1 pistons in the front
and #2 pistons in the rear.

Shock disassembly

The shocks must be removed from
the vehicle and disassembled to
change the pistons. Use the shock
exploded views included with the

B. Tighten/Loosen Lower Cap

model to aid in the assembly process.

1. Remove the spring and lower

spring retainer from the shock.

2. Remove the shock cap (A) and

empty the shock body of shock oil.

3. Remove the lower cap (B) and

the x-ring from the shock body.

4. Use side cutters to grip the shock

C. Remove/Install Rod End

shaft just above the rod end (C). Remove the rod end from the shock
shaft using the suspension multi tool (C).

5. Remove the shock shaft with piston from the shock body out through

the top of the shock body.

Shock assembly

1. Replace the stock piston with desired optional

piston. Be careful not to lose the small washer
located below the piston.

2. Position the new piston onto the shock shaft

above the small washer. Grip the threads of
the shaft with side cutters or needlenose pliers
and tighten the nut with the 4-way wrench to secure the assembly.

Piston Installation/Removal

3. Insert the shock shaft assembly through the shock body until the

piston bottoms out.

4. Lubricate the shaft and x-ring with silicone oil.

5. Install the x-ring over the shaft and into the bore of the shock body.

6. Install the lower cap using the suspension multi tool (B).

7. Slide the bump stop onto the shaft.

8. Grip the shaft close to the threads with needle nose pliers or side

cutters and thread the rod end onto the shock shaft until the rod end
bottoms out (C).

9. Fill the shock with new silicone shock oil up to the top of the

s

h

ock body. Slowly move the piston up and down (always keeping it
submerged in oil) to release the air bubbles. Let the shock sit for a
few minutes to allow any remaining air bubbles to surface.

10. Slowly thread the upper cap with the installed shock bladder onto the

shock body with the suspension multi tool (A). The excess oil will bleed
out of the small hole in the shock cap. Tighten the shock cap until
snug. Use the included steel shock wrench to hold onto shock body
while tightening.

11. Reinstall the spring and lower retainer.

Transmission and Differential tuning

Adjusting the Gear Ratio

The gear ratio on Revo can be adjusted for different conditions that may
require either increased acceleration or increased top speed. Adjusting the
gear ratio is accomplished by changing the clutch bell on the engine
and/or the spur gear (slipper clutch gear) on the transmission. From the
factory, Revo is equipped with a 15-tooth clutch bell and a 38-tooth spur
gear. This combination will provide a good balance of acceleration and
top speed. Optional spur gears and clutch bell gears are listed on your
parts list. Refer to the chart on page 45 for possible gearing combinations

Adjusting the Two-Speed Ratios

Revo is equipped to allow adjustment to the 2-speed by installing optional
close and wide-ratio gearsets. This requires transmission removal and
disassembly (see www.Traxxas.com for detailed instructions). The close
ratio gearsets will reduce top speed slightly but will provide more powerful
acceleration by reducing engine rpm loss when shifting from 1st gear to
2nd gear. The wide ratio gear set is designed for wide open areas and will
increase top speed, but reduce acceleration due to greater RPM loss when
shifting gears.

Advanced Tuning Adjustments

The following gear ratio chart shows the available combinations with
optional spur gears, clutch bells, and two-speed gear sets.

With 14T Clutch Bell

2nd gear sets

17T/39T

(Standard)

16T/40T

(Close)

18T/38T

(Wide)

With 15T Clutch Bell

(Standard)

2nd gear sets

17T/39T

(Standard)

16T/40T

(Close)

18T/38T

(Wide)

With 16T Clutch Bell

2nd gear sets

17T/39T

(Standard)

16T/40T

(Close)

18T/38T

(Wide)

Gear

1st

2nd

1st

2nd

1st

2nd

Gear

1st

2nd

1st

2nd

1st

2nd

Gear

1st

2nd

1st

2nd

1st

2nd

# of Spur Gear Teeth

36

24.21

25.55

16.79

17.72

24.21

25.55

18.30

19.31

24.21

25.55

15.45

16.31

# of Spur Gear Teeth

36

22.59

23.85*

15.67

16.54*

22.59

23.85

17.08

18.03

22.59

23.85

14.42

15.22

# of Spur Gear Teeth

36

22.36

21.18

15.51

14.69

22.36

21.18

16.9

16.01

22.36

21.18

14.27

13.52

*stock configuration out of the box

38

38

38

40

26.9

18.66

26.9

20.33

26.9

17.17

40

25.1

17.41

25.1

18.97

25.1

16.02

40

23.54

16.32

23.54

17.79

23.54

15.02

Tuning The Sealed Gear Differentials

Revo’s front and rear gear differentials allow the left and right wheels to
spin at different speeds while turning so that the tires do not scuff or skid.
This decreases the turning radius and increases steering performance.

The performance of the differentials can be tuned for different driving
conditions and performance requirements. The differentials are filled with
silicone differential fluid, and are sealed to maintain consistent
long-term performance. Changing the oil in the differential with either
lower or higher viscosity oil will vary the performance characteristics of the
differentials.

Changing to a higher viscosity oil in the differential will reduce the
tendency for engine power to be transferred to the wheel with the least
traction. You may notice this when making sharp turns on slick surfaces.
The unloaded wheels on the inside of the turn have the least traction and

tend to spin up to extremely high rpms. Higher viscosity (thicker) oil causes
the differential to act like a limited-slip differential, distributing more equal
power to the left and right wheels. Revo will generally benefit from higher
viscosity oil when climbing, rock crawling, or racing on low traction
surfaces.

Note: Heavier oil will allow power to be transferred even with

one or more tires off the ground. This can make the vehicle more likely
to overturn.

From the factory, both the differentials are filled with SAE 30,000W
viscosity silicone oil. Only use silicone oil in the differentials. Traxxas sells
SAE 10,000W and SAE 50,000W viscosity oil

(see your parts list). The
differentials have to be removed from the vehicle and disassembled to
change/replace oil.

Installing the Long Travel Rockers

Use the exploded views included with the model to aid in the installation
process. All of the rockers have labels identifying their proper location; RF
(right front), LF (left front), RR (right rear), and LR (left rear). Note: The
exhaust system must be removed to access the rear rocker arms.

1. Remove shock absorbers

Remove the screws that secure the shocks to the chassis shock mounts,
and to the rocker arms.

2. Install long travel shock springs

Replace all four of the 90mm travel shock springs with the four 120mm
long travel shock springs. The front shock springs are indicated by a silver
dot, and the rear shock springs are indicated by a blue dot.

3. Install long travel rockers

Replace the 90mm travel rockers with the long travel rockers by removing
the four 4x6 buttonhead cap screws from the rocker pivot posts. Remove
the 5x11 ball bearings from the rockers. Install the same 5x11 ball bearings
in the long travel rockers. Secure the long travel rockers to the pivots with
the same 4x6 buttonhead cap screws.

4. Locate push rods

Make sure that all four of the suspension push rods are located
and secured into the middle position (marked LT) on the lower
suspension arms.

5. Reinstall shock absorbers

Reinstall all four shock absorbers back into their respective locations.

Use higher viscosity
(thicker) oil for:

More power to the wheels
with the most traction.

Racing on low-traction
smooth surfaces .

Better performance for
climbing on uneven terrain.

Using lower viscosity
(thinner) oil for:

More power to the wheels
with least traction.

Racing on low-traction
rough surfaces.

Revo •45

Index

46 •Revo

.15, 20
ABC, 20
After-run maintenance, 18
After-run Procedure, 41
Air density, 31
Air filter, 6, 19, 20, 23, 33

foam, 20
maint

enanc

e, 18,23

oil, 5,23

Air intake, 19
Air temperature, 32
Air/fuel mixture, 24,
Air/fuel ratio, 24,
Airflow, 32, 33
Alignment, 36

bump steer,42, 43
c

ast

er,42
caster angle,42
configurations,37
maximum limits, 37
negative camber,36
positive camber,36
roll center,42
settings, 36
static camber,36
toe, 36

Altitude, 31
Ambient temperature, 32
Antenna (receiver), 7, 9,

, 6

mount

Antenna (transmitter), 9, 17
Atmospheric conditions, 18,
Axle carrier, 6
Axle pins, 8
Barometric pressure, 31
Baseline setting, 31
Batteries, 11,

alkaline, 5
c

e, 12

ar
charging, 11,12, 26
compartment, 9,11

25

25

13

16

24, 32

EZ-Start, 26
mAh, 10
NiCad (nickel-cadmium),5, 10,11
NiMH (nickel-metal hydride),10,
11
receiver,12
RX pack (5-cell pack), 5,9,10, 11
transmitter,11

Big block .15, 20
Body mount, 6
Brake, 6

adjustment, 39
link

age adjustment
pad wear and replacement,39
shoulder screw adjustment, 39
tension adjuster,6

Bulkhead, 6
Bumper, 6
Bumper Mount, 6
CA glue, 5, 8
Carburetor (carb), 19,

adjustments, 24
fine-tuning, 31
slide, 21
v

i, 24

entur

Channel, 9, 10, 16
Channel number, 10
Charger, 5, see also Batteries; charging
Charging jack, 6, 12, see also
Batteries; charging
Chassis, 6
Clean-out, 20
Clearing your frequency, 10
Clutch bell, 19,

mesh, 38

Combustion chamber, 20, 27
Compression, 21
Connecting rod, 20

maint

enanc

Cooling fins, 20
Crankcase, 19, 20

, 39

20, 24

45

e, 40

Crankshaft, 19, 20
Crashing, 33
Crystal (X-tal), 10, 16
Customer service, 3
Cylinder sealing, 28
Shocks (damper), 6

center-to-center distance,35
sho

ck oil,

35
pistons, 44
pre-load adjuster,6
replacing oil, 35

Decals, 8
Differential, 6

oil, 45
tuning

45

,

Drivetrain friction, 33
Driving, 33

tips, 33

Dyno, 20
E-mail, 3
Engine, TRX 2.5R, 18

"cutting out", 30
"sluggish",
break-in, 18,20, 21,22, 28

tank 1, 29
tank 2, 29
tank 3, 29
tank 4, 29
tank 5, 29
tank 6, 29

winter break in, 32
clearing a flood, 27
damage, 23
detonation, 30
failure, 23
hesitation, 30
high altitude operation, 29
overheating,21, 30
priming, 21,28
revving, 33
shut-off clamp,6, 19,27,31

21,

29, 30

shutting off,27, 29
stalling, 21,28, 30
starting, 26,27, 28
temperature,28, 30,32

cooling, 32
terms, 20
tuning, 24,25, 30,31

by temperature,32

Exhaust, 19, 20, 28
EZ-Start, 19,

c

ontroller,19
cush driv
drive unit,19
glow plug LED,27
motor,6, 19,27
motor LED,27
plug

Protection mode,27
Smart Start, 26
using

Fit, 20
Flag color, 10
Flame-out, 20
Flipping, 33
Flywheel, 19
Frequency band, 10
Fuel, 4, 5,

br
dispensing bottle, 5,22
flow,24
handling
other fuels, 22
unburned, 27,30

Fuel intake, 19
Fuel line (fuel tubing), 6, 19, 20, 27
Fuel mixture, 20
Fuel mixture needles, 24

20, 26

e, 26

,

6, 19
glow plug wire,19
ground wire,19
negative wire,19
positive wire,19

27

,

20, 22, 41

eak-in, 28

,

22

Index

Fuel tank, 6, 19

filling, 22

Fuel Cap, 6
Gear ratio, 44
Glow plug, 21

dr

er,21

iv
fouled, 28
glow plug wire,19, 27
igniter,26

Half shaft, 6
Head (cylinder head), 19, 20
Head protector, 19
Header, 6, 21
High-speed needle, 19,

adjustment

Humidity, 31
Idle speed, 21
Idle speed screw, 19, 21

adjustment, 25,31

Jumping, 33
Lean, 21

"leaning the mix
maximum safe lean setting, 30

Low-speed needle, 19, 21, 24

adjustment, 25,31

Lubrication, 22, 25, 32
Maintenance, 40

after-run, 41

Moisture, 33
Multi-tool, 5, 35, 44
Needle seat, 24
Needle valve, 21
Neutral position, 10
Nitromethane (nitro), 21

c

ont

percentage, 22,31

O-ring, 21
Obstacles, 33
On/Off switch (receiver), 6, 9, 16
OptiDrive, 6, 9,

pr

ogramming, 15

, 25,30

ent, 21,22

21, 24

ture", 21

10

Pinch test, 31
Pipe, 6, 19, 21

tuned, 21
Pipe hanger, 6
Piston, 21

maint

enanc

e, 40

Pivot balls, 6

adjusting pivot ball caps,35

Port, 21
Pressure line, 6, 19
Punch, 21
Push rods, 6
Quick Start, 7, 8,
22, 26, 27, 28, 30, 33, 40
Radio interference, 4
Radio system, 9

adjustments, 14

c

ontr

ols, 14
rules, 16
terminology,10

Range, 9, 12, 13, 16
Receiver, 6, 9,
Required equipment, 5
Reverse, 17
Rich, 21
Ride height, 34
Rockers, 6, 42

installing, 45

Roll hoop, 6
Rollover, 33
RPM, 21
RX Pack, 10
Safety, 4, 5,
Servo chart, 15
Servo reversing switches, 9, 15
Servo Saver, 39
Shift button, 9
Shift rod, 6
Shifting, 29
Shifting servo, 6, 9,
Shipping, 3

11, 12, 13

10, 16

, 33

8, 23, 41

, 16, 17,

10, 17

Skid plate, 6
Sleeve, 21

maint

enanc

e, 40

Slipper clutch, 6

adjusting, 37
pads

40

,

Smoke, 30
Spur gear, 6, 45

changing, 38
mesh,

38

Steering servo(s), 6, 9,
Steering system, 38

adjusting, 38
ser

o horn link, 39

v

Steering trim, 9, 10, 14
Steering wheel, 9
Storage, 40
Supplies, 5
Support, 3, 28
Suspension, 34

maximum limits, 37
r

ide height
rockers, 42
springs, 34
total travel,43
tuning, 34

Suspension arm, 6
Temperature gauge, 32
Throttle arm, 19
Throttle neutral adjust, 9, 14
Throttle trigger, 9
Throttle trim, 9, 10,
Throttle/brake servo, 6, 9, 17, 25
Tire gluing, 8
Tools, 5
Transmission, 6, 17

basic tuning, 37
gear r
two-speed access plug,6
two-speed adjustment, 38
t

w

, 35

atio

, 44

o-speed ratio,44

10, 17, 38

14, 17,

25, 31

Transmitter, 9, 10, 11, 14, 16, 17, 33

power indicator,9,11
p

wer switch, 9

o

Traxxas Lifetime Engine
Replacement Plan, 40
Trim, 10, see also Throttle trim,
Steering trim
Troubleshooting, 28
Tuning adjustments, 34

Advanced,42
B

, 34

asic

Toe link, 6
Two-speed, see Transmission
Wear-in, 21
Weather conditions, 31
Wheelies, 30, 33
Wheels, 8
Wiring Diagram, 9
WOT, 21
Y Adapter, 10

Revo •47

040428

owner’s manual

MODEL 5310

1100 Klein Road, Plano Texas 75074

1-888-TRAXXAS