OFNA Racing Ultra MBX R2 User Manual
THINGS NEED BESIDES THE KIT
3.5 cc (21 Class) ENGINE
REAR EXHAUST
Note: The engine may not include in kit.
REQUIRED FOR OPERATION
Glow Fuel
20%
Bottle’s with spout
# 10160 - large 500cc
# 10161 - large 500 ccAuto Stop
# 10162 - small 250cc
# 10164 - CNC spout 500CC
Off-Road Starter Box
# 10250 - 1/8 scale Starter Box
# 10253 - 1/8 scale Starter Box w/ Panel
Add-on
# 92571 - Power Panel Glow Heater
# 92572 - Cable for Glow Plug
Glow Plug Heat with Battery & Charger
# 10227....$$19.95
(please note OFNA Glow Heats available)
12V Battery for Starter Box
(must have)
AA Batteries ( 12 pcs ) for radio
RADIO CONTROL UNIT
Note: Careful read the instruction manual of your
2 channel radio controller before using.
SUITABLE SERVO SIZE
36mm-41mm
TOOLS NOT INCLUDED IN KIT
Phillips Type Screw Drivers ( L )
Phillips Type Screw Drivers ( S )
15mm - 21mm
29mm - 42mm
Cutter
Curved Scissors
Brush
Cross Wrench
#17109 $3.95
Instant Cement
Masking Tape
Radio must be set at neutral position
before installing in the kit.
SEQUENCE TO SET NEUTRAL
Install AA batteries in Radio.
Extend the antenna.(Transmitter)
Install batteries into Car receiver .
After installing the battery, connect the
battery box.
Extend the antenna. (Receiver)
Set the trim-leved at center.
Turn on the switch. (Transmitter)
Turn on the switch. (Receiver)
Make sure the servos are in command.
When the operation stick is in neutral,
servo horns must be in neutral as
will.
*Adjustment can be made by re installing the servo horn.
1111
Turn off the switch. (Receiver)
Turn off the switch. (Transmitter)
12
Retract the antenna. (Transmitter)
13
INCLUDED WITH KIT
More Optional Parts . . .
#10211 NiHm Battery Flat
Pack .. $29.95
# 10214 NiHm Battery Pack
Charger.. $7.95
OFNA/Picoo Glow Plug ..
$4.95
Shock Oil
1.5mm Allen Wrench
Needle Nose Pliers
Knife
Glow Plug & 17MM Cross Wrench
#10801 $6.95
2.5mm Allen Wrench
Paints
Grease Box
Grease
READ THIS BEFORE RUNNING
Running a nitro kit is fun and easy, but to make this a safe rusting.
and good experience you must observe a few rules. This
kit is extremely fast, easily over 40MPH, and can seriously
injure someone if you are not careful.
Where to run car?
• Any running area you choose must be dry. Do not run
car near any water or wet dirt.
• Do not run on public streets. It is very easy to have the
car run over or damaged by hitting the curb.
• Do not operate car in tight confined places. The car is
very fast and will easily hit something.
• Do not run near people or animals.
and will too easily hit someone.
• Due noise, you will want to consider the surrounding
area when operating the car.
• Do not operate the car at night. You will not be able to
drive it without hitting something.
• Do not operate the car indoors. Engine exhaust is not
healthy.
Glow Fuel
• Glow fuel is poisonous!
• Glow fuel is flammable!
• Do not leave in fuel bottle with lid off at any time. label for additional precautions.
• Don use any fuel other than glow fuel in this engine.
First Time Starting the Engine
Caution! When starting engine make sure the following is
observed. • Always turn off the car BEFORE turning off radio.
• Set engine Master needle to 3 turns (rich setting)
• Do not do this alone, get an experienced friend to help at • DAMAGE DUE CAR RUN AWAY IS NOT A WARRANTY
first. ISSUE.
• Fill fuel tank, try not to spill fuel. Do not spill fuel on
receiver
• Hold car off the ground, so it will not runaway when first
starts
• Turn on Radio and check the linkage before starting
engine.
• Turn on car receiver battery switch.
• Always have an air filter on the carburetor to keep dirt
out.
The car is very fast
• Clear oil and dirt from chassis with a degreaser.
Precautions
• This kit is not a toy. Always run car with a second
person as a spotter and pitman.
• Hot Parts - The pipe, manifold, engine and head are very
hot and will cause burns.
• Rotating Parts - Keep hands away from the drive train,
wheels, and engine when engine is running.
• Radio - Check batteries life before running the car. If
radio does not have full control of the car with steering
and/or throttle/brake do not run until corrected. Failure to
correct this will result in possible injury and damage to the
car or property.
• Glow fuel - Do leave the glow fuel unattended with the lid
off. Fuel contains Methanol and Nitro Methane and is
flammable and poisonous.
Store fuel in cool ventilated location. Refer the glow fuel
• Car Fuel tank - Never store fuel in car tank, it will ruin the
engine if left in tank.
IF YOU DO NOT BREAK-IN ENGINE
CORRECTLY, MAINLY AT LOW RPM,
YOU WILL BREAK THE CONNECTING
ROD!
Engine Break-in
• See Engine Page.
Emergency Stopping Engine When Running
• Remove air filter and cover carb. intake.
• Squeeze fuel line and hold until engine stops.
• With a rag, cover exhaust outlet.
Storing Car After Running
• Remove fuel from tank and fuel lines
• Turn off radio in car
• Put a few drops of after run in engine to keep it from
SHOCK ASSEMBLY
1mm
Washer
2mm
Washer
32237
Rebuild
7mm
E-Ring
* Note the E-Ring must
fit into groove as shown.
Kit
* Fit into groove.
Oil Seal
32203
Dust Pusher, Short
(Yellow Rubber)
Option:
32205
Dust & Shaft
Protector, long
*Push onto shock
cylinder.
32292
Front, 3.5mm
Short Shaft
Shock Shaft
* Short shaft
for front.
2.6 x 5mm
Washer
* Assembly 4 pieces of the
shock shaft .
30671
Front Shaft, 3.5mm
with Piston
Piston
2.6mm Nut
Sc
Ce
men
rew
t
32051
E-Ring
6mm Ball End
( Make 2 for front.)
( Make 2 for rear. )
32051
6mm Ball End
FILLING THE SHOCKS WITH OIL
1. Pull down piston and pour oil into
shock cylinder. Remove air bubbles
by slowly moving piston up and down.
Silicone
Oil
2. Pull down piston, attach pressure top
and shock oil overflow with tissue
paper.
*Leave 3mm.
32043
Cap, blue
32236
Rear, 3.5mm
Long Shaft
* Be careful not to damage shock shaft.
3. Tighten up shock cap.
* Long shaft
for rear.
30672
Rear Shaft, 3.5mm
with Piston
* Screw down cap.
UP
down.
*Move Slowly.
ASSEMBLY OF THE SPRING
Spring Holder
30403
6mm
Ball Joint
* Push 6mm ball joint
into ball end.
Optional...
32330
Set, Red Springs, Front & Rear
32340
Set, Yellow Springs, Front & Rear
32033
Pressure Top
Fit into groove.
*
32051
Misc. Plastic Shock Parts
*Slide spring collar into Shock.
Spring Collar
32051
Misc. Plastic Shock Parts
(Standard)
1mm
3mm
5mm
*Spring Tension adjust .er
ASSEMBLY OF NEW “K” STYLE DIFFERENTIAL CASE AND GEARS
31324 - FRONT OR REAR DIFF UNIT
31325 - CENTER DIFF UNIT
30779
2 x 12.8mm
Pin
* Position the O-ring
as shown.
30751 Diff. Case ( Front/Rear )
30761 Diff. Case (Center )
30779
2 x 12.8mm
Pin
30771
Diff. Shaft
30779
P5 O-Ring
( Orange )
30779
0.5 x 26mm
O-Ring
30769
Diff. Bevel Gear
( Large )
30779
4 x 10mm
Washer
* Apply diff. Gear grease to the
differential, during assembly.
* Fill the diff. Case to
approx 70% with grease.
Grease
30769
Diff.
Bevel Gear
( Small )
30773
4mm
Cross Pin
30769
Diff.
Bevel Gear
( Small )
30773
4mm
Cross Pin
30779
4 x 10mm
Washer
30769
Diff.
Bevel Gear
( Small )
30779
4 x 10mm
Washer
NB. It is very important to remove
the 30779 shim if the mesh
is too tight.
30771
Diff. Shaft
30769
Diff.
Bevel Gear
( Large )
ASSEMBLY OF THE BEVEL GEAR
( Builds two differentials for front and rear. )
30120
Bevel Gear
(Large/Metal)
31010
Optional - Bevel Gear
(Harden Steel)
30121
3mm
Tube
30779
P5 O-Ring
( Orange )
30121
3 x 5mm
Screw
30751 Diff. Case ( Front/Rear )
30761 Diff. Case (Center )
Sc
rew
Ce
me
nt
36730
Cap Joint
90026
5 x 5mm
Set Screw
30620
7 x 19mm
Bal lbearings
90026
5 x 5mm
Set Screw
3x10mm
Tapping Screw
3x10mm
Tapping Screw
Scre
Cem
w
t
en
* Push 3mm tubes into
holes of the diff. Case.
* Notice the straight holes
are for front and rear.
30121
3mm
Tube
30121
3 x 5mm
Screw
(Small Head)
5 x 5mm
Set Screw
3 x 5mm
Screw
30620
7 x 19mm
Ball bearings
39730
Cap Joint
30170
Brake Cap Joint
31040
Sc
Ceme
rew
nt
30620
7x19x5mm
Ball Bearing
30211
30620
7x19x5mm
Ball Bearing
90026
Screw
Cement
30170
Brake Cap Joint
30211
90026
5 x 5mm
Set Screw
30213
Brake Cam,
New
30171
Brake Lever Arm
Optinal:
30212
5x8x2.5mm
Flange Bearing
30180
Brake Pads
30190
Brake Disk
30201
Center Diff. Mount, new
30180
Brake Pads
30201
Center Diff. Mount, new
30180
Brake Pads
30652
Center Top Plate
(new)
30190
Brake Disk
30180
Brake Pads
30171
Brake Lever Arm
ASSEMBLY OF THE GEAR BOX
( Assemble two gear boxes for front and rear. )
30010
1
30630
6 x 13 x 5mm
Ball Bearing
* Insert two ball bearings
as shown.
3
Gear Box
30010
Gear Box
Screw
Cement
36730
Cap Joint
30630
6 x 13 x 5mm
Ball Bearing
2
5 x 5mm
Set Screw
* Make two gear boxes for front and
rear.
* Place set screw in D cut.
30130
Bevel Gear
Front Diff. Assembly
Note direction when installing!
3 x 20mm Flat Head
Tapping Screw
ASSEMBLY OF THE FRONT SHOCK TOWER
30160
Front Arm Pin
Holder
4 x 10mm
Tapping Screw
4 x 10mm
Tapping Screw
30010
Gear Box
Cover
30100
Front Shock Tower
4 x 20mm
Flat Head
Tapping Screw
Tower mounting
screws.
ASSEMBLY OF THE FRONT ARM HOLDER
3 x 20mm
Flat Head
Tapping Screw
1
0
4 x 15mm
Tapping Screw
( Small Head )
The gear box after assembled.
1
0
4x10mm
Tapping Screw
4 x 15mm
Tapping Screw
( Small Head )
30160
Front Lower
Arm Holder
ASSEMBLY OF THE FRONT
PIVOT BALL KNUCKLE ARM
* Use 5mm
hex wrench.
36904
14mm
Alum. Nut
36903
13.8mm
Steering Ball
36905
Steering Ball
Washer
36901
Ball Type
Knuckle Arm
( Right and Left )
R
* Note the "R" mark
is for righthand side.
36053
8x16mm
Ball Bearing
4 x 10mm
Tapping Screw
( Small Head )
Assembly of the right and left hand side
are the same.
* Adjust alum. Nut to
keep steering ball
smoot.
R
36053
8x16mm
Ball Bearing
36052
CVA
Constsnt Velocity Axle
ASSEMBLY OF THE FRONT KNUCKLE ARM
INTO FRONT ARM
36870
4 x 10 mm
Set Screw
36055
2.5 x 17mm
36054
Wheel Hub
( Alum. )
Pin
* Use 2.5mm
Hex Wrench.
R
36900
Front
Upper Arm
36890
Front
Lower Arm
Assembly of the right and left hand side
are the same.
* A 4 x 10mm set screw is used
to adjust the ride height.
36870
4x4mm
Set Screw
3mm
3.5mm
* Approx 3mm.
ASSEMBLY OF THE FRONT ARM ONTO GEAR BOX
Assembly of the right and left hand side
are the same.
5x5mm
Set Screw
* Do not over tighten
5x5mm set screw.
5 x 5mm
Set Screw
4 x 10mm
Tapping Screw
3 mm E-Ring
RR
* Insert drive shaft
before assembly.
3mm
E-Ring
30102
Front Body
Post
3x25mm
Cap Screw
1
0
3mm
Flange Nut
4 x 10mm
Tapping Screw
30151
Lower Arm Shaft
3mm
E-Ring
90021
3mm
E-Ring
RR
ASSEMBLY OF THE CASTER ADJUSTER
36905
Caster Angle
Adjuster
1
0
3x8mm
Tapping Screw
30152
Upper arm Shaft
3mm
E-Ring
* o change
the caster angle .
Caster angle will
become bigger.
use adjuster t
30701
3 x 3mm Set Screw
90021
3 mm E-Ring
3 x 8mm
Tapping Screw
Caster angle will
become less.
1
0
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