Cobra SRX8 Instruction Manual

INTRODUCTION

Thank you very much for selecting this Serpent rc car and thus become a member of the ever growing
worldwide Serpent racing family. Serpent started in 1980 and has been growing its product-line and fan

-base ever since.

The Serpent Cobra SRX8 is a state of the art 1/8 scale 4wd buggy which will give you the true Serpent
racing experience. The assembly manual will guide you through all the steps to complete the car, so you
can hit the track with a good base-set-up soonest. The Serpent design department succeeded to create a
superbly performing car combined with eas of assembly and maintenance. The high quality standards of
all parts and hardware will make racing your Serpent car a very rewarding activity !

Through our team, website and social media we will keep you up-to-date on all developments of the Serpent
cars. We hope to meet you on the track and through our various media! Enjoy the drive !

Team Serpent
Multiple World Champions

INSTRUCTIONS

Serpent’s long tradition of excellence extends to the instruction manuals, and this instruction manual is no
exception. The easy-to-follow layout is richly illustrated with 3D-rendered full-color images to make your
building experience quick and easy. Following the instructions will result in a well-built, high-performance
race-car that will soon be able to unleash its full potential at the racetrack. The kit includes bags, with

bagnumbers, which refer to the same step in the manual. Open only the indicated bag(s) per step and nish

that part of the assembly. Remaining parts will be needed lateron in the assembly process.

plaSTIC paRTS

The Serpent moulded parts are very durable and hard. When assembling longer screws in new composite
parts, make sure to use new hex bits in your (power) tools. Pre-threading also helps to avoid screw damage.

SETUp

In certain assembly steps you need to make basic adjustments, which will give you a good initial setup for
your Serpent Cobra SRX8. Fine-tuning the initial setup is an essential part of building a high-performance
racecar like your Serpent Cobra SRX8.

EXplODED VIEWS aND paRTS lIST

The exploded views and parts lists for the Serpent Cobra SRX8 are presented in the Reference Guide
section in the back of this manual. The exploded views show all the parts of a particular assembly step
along with the Serpent part number and hotlink to the Serpent website. Partnumbers in orange indicates
that this part is an optional. Optionals part names and numbers are showed below.

CUSTOmER SERVICE

Serpent has made a strong effort to make this manual as complete and clear as possible. Additional info
may be published in our website: www.serpent.com or you may ask your dealer or the Serpent distributor
for advice, or email Serpent direct: [e-mail]. The Serpent Facebook, Twitter and Youtube pages
give additional means of support and communications.

SafETy

Read and take note of the ‘Read this First section’ before proceeding to assemble the car-kit. This car-kit is
intended for persons aged 16 or older.

REaD ThIS fIRST!

- This is a highly technical hobby product, intended to be used in a safe racing environment. This car
is capable of speeds in excess of 80 km/h or 50mph. Please follow these guidelines when building and
operating this model.

- Parental guidance is required when the builder/user of this car is under 16.

- Follow the building instructions. If in doubt, contact your dealer or importer.

- Be sure to use the proper tools when assembling the car. Always exercise caution when using electric
tools, knives and other sharp objects.

- Be careful when using liquids like lubrication oil, fuel or glue. Do not swallow.

- Follow the manufacturer’s instruction in case you experience irritation after using the product.

- Be careful when operating the car. Stay away from any rotating parts such as wheels, gears and
transmission. Stay away from motor, engine and exhaust pipe system or speedo during and immediately
after use, as these parts may be very hot. We advise to use protective hand cloves.

- Only operate this car in a safe environment, like a special racing track or a closed parking lot. Avoid using
this car on public roads, crowded places or near infants.

- Before operating this car, always check the mechanical status of the car. Also check that the transmitter
and receiver frequencies correspond and are not used by any other racer at the same time. Check that the
batteries of the transmitter and receiver- are fully charged.

- After use, always check all the mechanics of the car. We advise to clean the car immediately after use,
and inspect the parts for wear or fractures. Replace when necessary. Do not use water, methanol, thinner
or other solvents to clean the car.

- Empty the fuel tank (depending on model) if needed and disconnect the receiver battery.

- Store the car in a dry and heated place to avoid corrosion of metal parts.

- Avoid using this car in wet conditions as the water will cause corrosion on the metal parts and bearings
and these parts will cease to function properly. If driven in the wet, ensure that all the electric equipment is
waterproofed and after use, that all moving parts are dried immediately.

CONTENTS

•

CENT ERDIFF ASSE MBLY   4

•

FR/RRDIFFASSEMBLY   6  

•

CENTRALASSEMBLY    8

•

REARASSEMBLY    11

•

FRONTASSEMBLY18

•

STEERINGASSEMBLY24

•

RADIOASSEMBLY28

•

SHOCKASSEMBLY    32

•

FINALASSEMBLY35

•

CLUTCHASSEMBLY36

•

EXPLODEDVIEWS42

•

TEA MSERP ENTN ETWORK   53

3

hOW TO USE ThE maNUal

Each step contains a variety of numbers, lines, and symbols. The numbers represent the order in
which the parts should be assembled. The lines are described below.

Each step contains a variety of symbols described below.

Assembly path of one item into another

Group of items (within lines) should be
assembled first

Direction the item should be moved

Glue one item to another

Press/Insert one item into another

Connect one item to another

Gap between two items

ICONS DESCRIpTIONlINES DESCRIpTION

Carefull, read and check very well.

Apply a small amount of cyano glue. Use wear protection for eyes and hands.

Detail view to explain assembly or order of parts better.

Default set-up: This symbol indicates the default setup.

Grease: apply a small amount of grease to the parts shown.

Left and right parts should be assembled in the same way.

Silicone oil: use the indicated silicone oil for the shocks and differentials.

Parts or items not included in the kit.

Optional part, not standard in the kit.

Thread lock: apply a small amount on the parts shown. Before to apply the threadlock,
make sure to degrease the parts very well, as otherwise the threadlock will not work.

Step number; the order in which you should
assemble the indicated parts

1 32

Length after assembly

4

CENTER DIff aSSEmbly

6x11.75x0.2

6x11.75x0.2

8x16x5

8x16x5

M3x4

2.5x12

2.5x12

Use silicone oil to
hold seal in position.

STEp 1

CENTER DIff bag

1.1

1.2

3

1

2

8x16x5

6x11.75x0.2

2.5x12

M3x4

STEp 2

Add just enough oil to cover the large gear
before assembling the small satellite gears and
cross pins.

Use the silicone oil supplied in the kit. For the
correct cst value please check the default
setupsheet.

2.2

2.1

Note the correct
pin location.

Note the correct pin location.

14.7 - 14.9 mm

VOLUMECOMPENSATORS

When the differential gets hotter, the foam
inserts will absorb the pressure of the expansion
of the oil.
1- The supplied foam tube must be cut to size as
indicated here below.
2- Penetrate them fully with same differential oil .
3- Insert them in the compensator holes.

5

STEp 4STEp 3 STEp 5

M3x14

3.5x7x0.1

M3x14

Fill the differential with silicone oil 1 mm above the crosspin, do NOT

overll. Use the silicone oil supplied in the kit. For the correct cst value

please check the default setupsheet.

Use a digital scale to measure the
exact amount of oil in the diff.

Differential weight with volume
compensators = 40.8 grams

Differential weight without volume
compensators = 41.0 grams

1mm

AMOUNT OF OIL IN
THEDIFFS

OILLEVEL

3.5x7x0.1

3.5x7x0.1

6

fR/RR DIff aSSEmbly

STEp 6 STEp 7

fR/RR DIff bag

6x11.75x0.2

6x11.75x0.2

8x16x5

8x16x5

M3x4

2.5x12

2.5x12

Use silicone oil to
hold seal in position.

6.1

7.2

7.1

6.2

3

1

2

Add just enough oil to cover the large gear
before assembling the small satellite gears and
cross pins.

Use the silicone oil supplied in the kit. For the
correct cst value please check the default
setupsheet.

8x16x5

6x11.75x0.2

2.5x12

M3x4

Note the correct
pin location.

Note the correct
pin location.

14.7 - 14.9 mm

VOLUMECOMPENSATORS

When the differential gets hotter, the foam
inserts will absorb the pressure of the expansion
of the oil.
1- The supplied foam tube must be cut to size as
indicated here below.
2- Penetrate them fully with same differential oil .
3- Insert them in the compensator holes.

7

STEp 9STEp 8 STEp 10

M3x14

3.5x7x0.1

M3x14

Fill the differential with silicone oil 1 mm above the crosspin, do NOT

overll. Use the silicone oil supplied in the kit. For the correct cst value

please check the default setupsheet.

1mm

Use a digital scale to measure the
exact amount of oil in the diff.

Differential weight with volume
compensators = 40.15 grams

Differential weight without volume
compensators = 40.35 grams

AMOUNT OF OIL IN
THEDIFFS

OILLEVEL

3.5x7x0.1

3.5x7x0.1

8

CENTRal aSSEmbly

STEp 12STEp 11

bag 1

1

2

12.1

12.2

M3x16

Flanged

M3x6

M3x16 Flanged

M3x6

Front

Front

Front

Rear

Rear

Rear

Diff mounts are NOT symmetrical.

Please check below picture to
ensure front and rear bracket assembly are
assembled properly.

Do NOT overtighten
the screws.

9

STEp 13

M4x12

M4x12

10

STEp 14 STEp 15

14.1 14.2

M3x12

Nylock nut M3

3.2x7x0.5

M3x10

M3x4

M3x4

1

1

2

2

3

4

M3x12

3.2x7x0.5

Nylock Nut M3

M3x4

Note the correct brake wires
position.

M3x10

Front

Long

Short

Rear

FrontRear

The long cam is
assembled in the front
bracket, the short one
in the rear bracket .

BRAKE
CAMS

11

REaR aSSEmbly

STEp 16 STEp 17

Note the correct grommet position.

After building the differential with new gears, new dif ferential case
and bearings, the diff may feel a lit tle tight. The connected parts need

at least an hour run-time to create a per fect match. Attention: When
you assemble the diff with too much initial play, the gears will not run-in
properly and may wear quickly. After 1 or 2 hours of
running the car, re-check the gear-mesh between the
ring gear and the pinion. All parts should have run-in
properly n ow. You may add or remove 8x 11x0.1 shims
as needed.

16.1

16.2

1

2

3

4

2.5x13

8x16x5

8x11x0.1

5x13x4

M5x6

M3x14

M3x12

Flanged

1

2

2

3

8x11x0.1

2.5x13

8x16x5

5x13x4

M3x14

M3x12 Flanged

Note the correct
coupler assemby.

bag 2

12

STEp 18 STEp 19

18.1

18.2

13x16x0.1

M3x22

13x16x0.1

2

1

1

M3X16

M3x22 M3x16

13x16x0.1

After 1 or 2 hours
of running the car,

re-check the gear­mesh between the ring gear
and the pinion. All parts
should have run-in properly.
You may add or remove
13x16x0.1 shims as needed.

13

2

3

4

1

M2.5X6

M2.5X6

STEp 20 STEp 21

M3X16

20.1

20.2

REARTOEININSERTSCHART REARANTISQUATINSERTSCHART

M3x16

M2.5x6

bag 3

34 mm

ANTIROLL BAR
RODLENGTH

Tighten anti-roll bar cap until
there is no play, and it moves
freely.

14

STEp 23STEp 22

REARANTIROLLBARASSEMBLY

Make correct holes in the
mudguards as required.

M3X3

M3X8

M3X8

M3X3

5X8X2.5

Flanged

M3x3

5X8X2.5 Flanged

M3x8

15

STEp 24

3x17

13x19x4

8x16x5

M3x6

2.5mm

1.25mm

Nylock Nut M3

M5x4

2.5x13

24.1

24.2

4

3

5

6

1

2

7

8

M3x6

2.5x13 3x17
Nylock Nut M3

8x16x5

13x19x4

M5x4

bag 4

Note the correct
coupler assemby.

REAR UPRIGHT ROLL
CENTERINSERTS CHART

LOW

MID LOW

MID HIGH

HIGH

REARDEFAULT
WHEELBASESHIMS

Apply shims s ize 8x11x0.1
and/or 8x11x0.2mm as
needed to remove play.

8x11x0.1

8x11x0.2

16

25.1

25.2

STEp 25

M3X20

M3X20

3.2x7x0.5

Nylock Nut

M3 Flanged

Nylock Nut M3

1

2

M3x20 3.5x7x0.5

Nylock Nut M3

Nylock Nut M3

Flanged

M3x20

bag 5

17.7 mm

REARCAMBERLINKLENGTH

REARCAMBERLINK
DEFAULTPOSITION

17

STEp 26

M3X25

M3X16

Nylock Nut

M3

STEp 27

M4x12

M4x20

Nylock Nut M3

M3x25 M3x16

M4x12M4x20