Cobra DCX65 2003 Owner's And Service Manual

Brand: Cobra

Model: DCX65 2003

Category: Motorcycles

Type: Owner's And Service Manual

2003 DCx65

Owners / Service Manual

“CHAMPIONS START HERE”

For parts orders contact your local dealer

To locate your closest Cobra dealer

log on to

www.cobramotorcycle.com

or call

(330) 549-9600

If you need technical assistance

contact your local dealer or call

the Cobra Technical Support Hotline at

(330) 549-9603

Cobra Motorcycle MFG., Inc.

11511 Springfield Road

North Lima, Ohio 44452 MCDC2003.1

DISCLAIMER OF WARRANTY

This motorcycle is sold “as is” with all faults, obvious or not. There are no warranties

expressed or implied, including any warranty of merchantability and warranty of fitness

for any particular purpose.

“WARNING”

THE COBRA DC65 IS A COMPETITION MODEL ONLY AND IS NOT

MANUFACTURED FOR, NOR SHOULD IT BE USED ON PUBLIC STREETS, ROADS

OR HIGHWAYS.

THE USE OF THIS BIKE SHOULD BE LIMITED TO PARTICIPATION IN

SANCTIONED COMPETITION EVENTS UPON A CLOSED COURSE BY A

SUFFICIENTLY SKILLED RIDER AND SHOULD NOT BE USED FOR GENERAL

OFF-ROAD RECREATIONAL RIDING.

IMPROPER USE OF THIS MOTORCYCLE CAN CAUSE INJURY OR DEATH.

THIS BIKE IS INTENDED FOR EXPERIENCED RACERS ONLY AND NOT FOR

BEGINNERS.

IT IS YOUR RESPONSIBILITY AS THE OWNER OF THIS COBRA MOTORCYCLE

OR AS THE PARENT, OR LEGAL GUARDIAN OF THE OPERATOR, TO KEEP THIS

COBRA MOTORCYCLE IN PROPER OPERATING CONDITION.

THIS BIKE WAS DESIGNED FOR RIDERS THAT WEIGH LESS THAN 80 LBS WITH

FULL RIDING GEAR AND SHOULD NOT BE OPERATED BY RIDERS THAT WEIGH

MORE THAT.

BE SURE THAT THE RIDER ALWAYS WEARS ADEQUATE SAFETY GEAR

EVERYTIME HE OR SHE RIDES THEIR COBRA MOTORCYCLE.

IMPORTANT SAFETY NOTICE

Failure to follow WARNING instructions could result in severe injury or death to

the machine operator, a bystander, or a person inspecting or repairing the

machine.

CAUTION:

A CAUTION indicates special precautions that must be taken to avoid damage to

the machine.

NOTE:

A NOTE provides key information to make procedures easier or clearer.

Table Of Contents

General Information.........................................................................................................5

Specifications - General..............................................................................................5

Specifications - Torque Values ..................................................................................6

Specifications – Suspension.......................................................................................8

Optional Components......................................................................................................9

Break-In Procedure....................................................................................................10

Starting Procedure.....................................................................................................11

General Tips................................................................................................................12

Maintenance....................................................................................................................13

Schedule & Tips .........................................................................................................13

M1: Replacing Transmission Lubricant...................................................................14

M2: Chain adjustment................................................................................................15

M3: Front brake adjustment......................................................................................16

M4: Clutch lever adjustment.....................................................................................16

M5: Rear brake adjustment ......................................................................................17

M6: Air Filter Cleaning ...............................................................................................18

M7: Fork Oil Replacement........................................................................................19

Engine Parts / Service...................................................................................................20

ES1: Top End Parts ...................................................................................................20

ES2: Bottom end & transmission.............................................................................20

ES3: Clutch and Shifter components......................................................................21

ES4: Ignition................................................................................................................24

ES5: Cooling System.................................................................................................25

ES6: Fuel & Air System.............................................................................................25

ES7: Exhaust ..............................................................................................................26

Tuning ..............................................................................................................................27

Tuning 1: Carburetor..................................................................................................27

Jetting Decisions ....................................................................................................27

Jetting Changes......................................................................................................30

Tuning 2: Suspension................................................................................................34

1 Suspension Guidelines ......................................................................................35

2 Proper Suspension Adjustments for Your Rider............................................36

3 Symptoms of Incorrect Suspension Adjustment............................................40

4 Proactive Suspension Adjustments .................................................................41

5 How to Adjust the Suspension..........................................................................42

6 Suspension Reference.......................................................................................43

Troubleshooting..............................................................................................................44

Index.................................................................................................................................45

General Information

Specifications - General

Items DC65

Dimensions

Wheelbase 44.75” (1136 mm)

Wheel size 14” (356 mm) front, 12” (305 mm) rear

Seat height

Engine

Type 2-stroke, single cylinder, reed valve

Cooling system Liquid-cooled

Displacement 64.8 cc (3.95 Cubic inches)

Bore and stroke 43 mm x 44.6 mm

Ignition system Electronic

Spark plug Splitfire SF406B

Gap

0.023” – 0.025” (0.58 – 0.64 mm)

Fuel type Sunoco MO2X or 93 octane pump gasoline

OTHER RACE FUELS ARE NOT RECOMMENDED

Oil type Cobra Venom 2-cycle Race Oil

Fuel / oil mix ratios 32:1 to 40:1

Ignition timing 0.050”

Carburetion 28 mm PWK style

Main jet

128

Slow (Pilot) jet

Jet needle

JJH 3rd position from the top

Float height

19 mm + 0.5mm (0.75” + 0.020”)

Transmission

Speed Six speed

Clutch Manual hydraulic

Final drive ratio 13/46 T

Transmission / clutch oil type 85W 90 Gear Lubricant

Quantity

530 ml (18 oz)

Chassis

Front tire 60/100 x 14

Pressure

10 - 15 psi.

Rear tire 80/100 x 12

Pressure

10 - 15 psi.

Front fork Cobra USD 35 mm

Fork oil type

SAE 5 weight

Fork oil amount

4 oz (118 ml)

Fork oil level

Specifications - Torque Values

Torque Value

ENGINE Fastener ft-lb in-lb Nm

Size &

Remarks

Cylinder head nuts 9.2 110 12 ¼” x 20

Engine oil drain 3 36 4 8 x 1.25

Engine oil fill 2 24 2.7 14 x 1.0

Spark Plug (SP)

(SP) (SP)

14 x 1.25

Crank case half 5 60 6.8 6 x 1.0

Crank case cover 5 60 6.8 6 x 1.0

Flywheel rotor nut 40 480 54 10 x 1.25 (G)

Clutch hub 40 480 54 10 x 1.25 (G)

Units of mm unless otherwise specified

(G) denotes the use of wicking / bearing retainer (green) thread locking agent to

applied to the mating surfaces of the two components but not the threads.

(SP) To apply the proper torque to the spark plug when inserting, one must first

screw the spark plug in until the metal gasket ring causes resistance and then

turn another 1/8 to ¼ turn.

Torque Value

CHASSIS Fastener ft-lb in-lb Nm

Size &

Remarks

Front axle nut 25 300 34 12 x 1.25

Front brake caliber 22 264 30 8 x 1.25

Front brake rotor 6 72 8 6 x 1.0 (B)

Triple clamp bolts 6 72 8 6 x 1.0

Fork cap 5 60 6.7 1.25” x 18

Steering head 30 350 40 1.0” x 12 (R)

Handle bar mounts 15 177 20 8 x 1.25

Handle bar clamps 15 177 20 8 x 1.25

Front engine mount 22 265 30 8 x 1.25

Rear brake lever pivot 10 120 13.6

8 x 1.25

Subframe fasteners 22 265 30 8 x 1.25

Upper shock mount 40 480 54 10 x 1.5

Lower shock mount 40 480 54 10 x 1.5

Swingarm pivot 21 250 28 14 x 2.0

Rear axle nut 25 300 34 12 x 1.25

Rear sprocket bolts 13 160 18 8 x 1.25 (B)

Rear brake caliper bolts 22 264 30 8 x 1.25

Rear brake rotor bolts 6 72 8 6 x 1.0 (B)

Units of mm unless otherwise specified

(R) designates that the application requires the use of high strength (red) thread

locking agent applied to the threads.

(B) designates that the application requires the use of medium strength (blue)

thread locking agent applied to the threads.

Specifications – Suspension

Factory

setting Track 1

Track 2

Track 3

Track 4

Fork Oil

Viscosity

5 wt

Oil Height

(amount)

4 oz

(118 ml)

Fork Spring

STD.

Shock Spring

STD.

Preload height

Rebound

Damping (clicks

from full damp)

Compression

Damping (clicks

from full damp)

Optional Components

• Carburetor jets

• Sprockets

o Front

o Rear

• Suspension Springs

Weight of Rider (lb) Fork Spring Shock Spring

Less than 51 - SCDC0285 (285 lb/in)

51 - 60 KCDCSP01

(blue, 14 lb/in) SCDC0300 (300 lb/in)

Greater than 60 KCDCSP02

(red, lb/in) SCDC0325 (325 lb/in)

SCDC0350 (350 lb/in)

• Suspension Valving

Damping Rate Fork Valving

Compression

(base valve)

Fork Valving

Rebound

(mid valve)

Shock Valving

(kit)

Soft (fast) KCDCBV01 KCDCMV01 SCDCOH01A

Standard KCDCBV02 KCDCMV02 SCDCOH01

Hard (slow) KCDCBV03 KCDCMV03 SCDCOH01B

• Flywheel weights

o Middle weight #ECDC0200

o Heavy weight #ECDC0201

Break-In Procedure

Your Cobra Motorcycle is a close-tolerance high performance machine and

break-in time is very important for maximum life and performance. The DC65 can

be ridden hard after the first ½ hour break-in time but it is recommended that no

adjustments are made to the carburetion or suspension until the full 8 hours of

bike break-in has elapsed. Also, after the engine, transmission, and drive train

have been broken-in for the full 8 hours, the bike will be faster!

Use a fuel / oil mixture of 32:1 for the full 8 hour break-in period. Be sure to use

93 octane pump gas, or Sunoco MO2X , with Cobra’s specially formulated Cobra

Venom 2-cycle Race Oil. (Part # MCMUOL02)

CAUTION:

Failure to use proper fuel or oil may result in premature engine wear, or damage

to the machine.

Adhering to the following break-in schedule will result in long lasting high

performance machine.

• First ½ hour of operation

o Follow the starting procedure listed in this manual.

o Avoid prolonged operation at Wide Open Throttle.

• After 1 hour of operation

o Check for loose bolts and nuts on the bike and retighten as

necessary (proper toque values are listed under Specifications).

o Clean the carburetor bowl.

o Change the transmission / clutch lubricant.

o Replace the fuel filter.

• After 8 hours of operation

o Change the fork oil.

o Have a Certified Cobra Mechanic change the shock oil.

• Your bike is now ready for the highest level of competition!

Starting Procedure

Before starting the machine inspect the following:

• Insure that the fuel tank contains an adequate volume of fuel / oil mixture to

complete the distance required. (Sunoco MO2X or 93 octane pump gas with

Cobra’s specially formulated Cobra Venom 2-cycle Race Oil)

• Check for proper tire pressure in both tires.

• Observe the chain tension and adjust if necessary.

• Observe the coolant level and fill if necessary.

• Verify that the chain rollers do not have improper wear.

• Inspect the frame, for;

o Cracks in the metal.

o Cracking paint which might indicate overly stressed material.

• Verify that the handlebars are tight.

• Check the throttle for;

o Smooth operation and sound closing.

o Frayed strands of the cable inside the throttle housing.

• Check for loose bolts and nuts, and re-torque as necessary.

• Verify that the air filter is clean and properly saturated with oil.

• Turn the fuel on by rotating the fuel petcock knob to the vertically downward

position (reserve position is horizontally forward).

CAUTION:

For best results from your Cobra Motorcycle use only the recommended fuels.

Testing has shown that most ‘race’ fuels actually degrade performance.

When your pre-ride inspection is complete the bike may be started. For a cold

engine follow this procedure.

1. Reaching down to the carburetor, on the left side of the bike, pull up the

black choke knob and rotate it so that it locks in this ‘up’ position.

2. Kick start the engine.

3. Rev the engine in short spurts, turning the throttle no more than 1/4 open

until the engine will run without the choke.

4. Verify a functional engine shut-off switch by shutting off the engine.

5. Restart the engine and proceed with riding when the engine is sufficiently

warm (i.e. the side of the cylinder is warm to touch).

CAUTION:

Never rev an engine full throttle when it's cold or slightly warmed up. Cobra

recommends that you tell your child to take it easy the first couple of minutes in

practice until the engine comes up to full operating temperature. Make sure your

engine is properly warmed up before racing.

General Tips

1. Always wear a helmet and other protective riding gear.

2. Cobra recommends that you tell your child to take it easy the first couple of

minutes in practice until the engine comes up to full operating

temperature.

3. Make sure your riders’ foot is not resting on the rear brake pedal while they

are riding.

4. Evaluate the bikes jetting only after it has been warmed up to race

temperatures.

5. A properly maintained machine is safer, faster, and more fun to ride.

6. When washing the bike, be careful to not directly aim the hose at the

bottom edge of the seat, or water is apt to enter the airbox.

7. Some people have found cable ties (zip ties) more favorable for securing

the rear brake line to the swingarm.

8. Also, some people are moving the rear brake line (hose between the

master cylinder and the reservoir) from it’s stock position, to a position

slightly more forward and securing it with a cable tie (zip tie). This moves it

further from the heat of the exhaust pipe.

9. Mare sure that there is adequate free play in both the front lever and rear

brake pedal.

10. Your Cobra Motorcycle has a 12 digit VIN (Vehicle Identification Number).

The first four digits indicate the model and the nineth indicates the model

year (MY).

a. The exception is that ’03 MY DC65 which came out late so the

model year is off by one.

b. Example, DC65-xxx-x2xxx is a 2003 MY DC65.

Maintenance

Schedule & Tips

It is important that you adhere to this maintenance schedule so as to promote the

longevity of your Cobra Motorcycle.

• Between each ride

o Inspect the fuel filter for contaminates.

o Check the air filter (clean and re-oil as necessary).

o Insure the smooth operation of the throttle cable (throttle soundly

‘clacks’ shut).

o Check for frayed strands of the throttle cable inside the throttle housing

and replace if necessary.

o Check for adequate tire pressures and adjust if necessary.

o Check all nuts and bolts for proper torque and re-torque if necessary.

o Spray all moving parts with WD40 or other light oil.

o Check drive chain for

§ Proper tension and adjust if necessary.

§ Adequate lubrication and lubricate if necessary.

o Insure that the ignition stator and rotor are clean and dry.

o Check the frame for cracks in the metal or cracks in the paint that

might indicate that the metal has been stressed beyond it’s safe limits.

Replace or get properly rewelded as necessary.

• Every 2 hours of operation

o Replace the transmission oil.

• Every 10 hours of operation

o Replace the fork oil.

o Have the shock oil replaced by a Certified Cobra Mechanic.

CAUTION:

1. If you ever need to weld anything on the bike, disconnect the spark plug

cap, unplug the ignition, disconnect the kill switch, scrape the paint bare

near the area to be welded and put the ground clamp as close to the area

to be welded as possible.

Be sure the fuel tank and carburetor have been removed and safely located

away from the welding process.

2. The frame is 4130 Chrome Moly and it is important to weld it with the proper

rod and heat settings set as light as possible. Cobra recommends replacing

the frame with a new one if the old one becomes damaged.

M1: Replacing Transmission Lubricant

Tools needed:

• 530 ml (18 oz) 85W 90 gear lubricant

• large flat blade screwdriver

• 13 mm wrench or socket

Procedure:

1. Begin this procedure with a bike that has been ridden more than 5 minutes

but less than 10 minutes. It is desired to have the engine warm enough so

that the oil ‘runny’ but not so hot that there is risk of being burned by the

engine or the oil.

Hot oil and hot components on the motorcycle may cause burns.

2. Lean bike against something or set on stand with oil drain hole.

3. Using the 13 mm wrench, remove the oil drain bolt located on the right side

of the engine (figure 1).

Figure 1

4. After it has drained, reinstall the drain screw with gasket.

5. Remove the oil fill plug and pour in 530 ml (18 oz) 85W 90 gear lubricant.

NOTE: Leaning the bike over onto it’s left hand side will facilitate the oil filling

procedure.

6. Reapply the oil fill screw, securely, being sure the gasket is in place.

M2: Chain adjustment

Tools needed:

• Two 19 mm wrenches or sockets

• 13 mm wrench or socket

• Measuring device

Procedure:

1. Loosen the rear axel nut (two 19 mm wrenches).

2. Adjust the chain adjusters in the end of the swingarm (clockwise for tighter

chain) until proper chain tension, 37 – 42mm (1.50” – 1.63”) is achieved (13

mm wrench). See figure 2 for proper measurement location.

NOTE:

This measurement is to be made with the motorcycle setting on a stand and

the rear wheel suspended in the air while lifting on the chain.

Figure 2

3. From the back, sight down the length of the chain to confirm that the rear

wheel is running true (rear sprocket is not forcing the chain to turn).

4. Verify that the wheel is all the way forward against the adjusters.

5. One way to do this is to place a shop rag between the chain and sprocket

while rotating the wheel backwards (figure 3) thus pulling the wheel forward.

Figure 3

6. Tighten the rear axel nut to 25 ft-lb (34 Nm) (two 19 mm wrenches).

Rotate the wheel forward and remove the shop rag.

M3: Front brake adjustment

Tools recommended for front brake maintenance:

• 10mm open end wrench

• 3 mm hex key

CAUTION:

Adequate lever free play is required so that the brake pads do not wear

prematurely.

1. Loosen the lock nut (10mm wrench).

2. Screw the adjuster in (Clockwise) to remove free play, or out (Counter

Clockwise) to add free play (3mm hex key).

M4: Clutch lever adjustment

The clutch lever adjuster requires no tools. Rotate the red adjusting knob in

(Clockwise) to remove free play, or out Counter Clockwise) to add free play

M5: Rear brake adjustment

Tools required

• 10 mm wrench

1. Set pedal position first, then

2. Set pedal free play.

Setting rear brake pedal position (see figure 4):

1. Loosen the lock nut (10mm wrench).

2. Adjust the brake lever stop (10mm wrench) so that the lever is comfortably

reachable in both:

a. Standing riding position, and

b. Sitting riding position.

3. Tighten the lock nut (10 mm wrench).

Figure 4

Setting rear brake pedal free play

CAUTION:

Adequate pedal free play is required so that the brake pads do not wear

prematurely.

To adjust (see figure 4):

1. Loosen the lock nut (10mm).

2. Undo the free play locking clip from around the brake adjuster (plunger),

with your hand by pushing it forward.

3. Slide the pin of the locking free play locking clip from the brake lever

4. Adjust as needed by rotating the clevis on the end of the adjuster (plunger).

NOTE:

Turning the clevis Clockwise will lengthen the adjuster (plunger), removing free

play from the system, and turning the clevis Counter-Clockwise will shorten the

adjuster (plunger) adding free play to the system.

M6: Air Filter Cleaning

This Cobra Motorcycle comes with a unique air filter / air boot unit designed to

facilitate motorcycle service.

Tools recommended for air filter maintenance:

•

• Foam filter oil

Procedure

1. Removed the front fastener from the left side number plate (?? Hex key).

NOTE:

This fastener holds a spacer between number plate and the frame, which will

drop into the airbox when the fastener is pulled from the number plate. Merely

grab the spacer with one hand while removing the spacer from the number plate

with the other.

2. Rotate the number plate counter clockwise (downward) exposing the

aluminum air box side plate.

3. Remove the two fasteners holding the air box side plate (Hex key)

4. Separate the air filter from the carburetor a

5. Clean the filter with cleaning solvent and then again with hot soapy water.

6. Allow it to dry thoroughly.

7. Saturate with foam filter oil and remove excess.

Do not clean the air filter with gasoline or other highly volatile petroleum product.

Cleaning solvent, diesel fuel, or kerosene would be preferred but caution should

still be taken.

NOTE:

The biodegradable air filter oils, greases, and cleansers work acceptably with this

Cobra Motorcycle.

CAUTION:

Cobra does not recommend using the spray on air filter oils due to their limited

saturation.

NOTE:

It is very important to keep the air filter clean and properly oiled with high quality

water-resistant foam filter oil. It’s very important to oil your filter consistently each

time because varied amounts of oil will change your carburetor jetting.

NOTE:

Make sure you change or clean your filter after each moto. We recommend

carrying three or more filters in your toolbox.

• 1 for practice

• 1 for each moto

CAUTION:

It is recommended to apply medium strength (blue) thread locking agent to the

threads of the air box side fasteners as well as the number plate fastener.

M7: Fork Oil Replacement

Tools required

• Two 19 mm sockets or wrenches

• 4 & 5 mm hex key (Allen wrench)

• 10 mm wrench

• 1” wrench or socket

NOTE:

It is strongly recommended that you leave the front brake caliper attached to

the fork leg for this procedure. The mounting bolts are all that hold the two

halves of the caliper together, and disassembly would require bleeding the brake

system.

Disassembly

1. Remove the front wheel (19 mm wrenches).

2. Remove the front brake lever perch from the handlebars (4 mm hex

3. Remove the fork legs from the triple clamps (5mm hex key).

4. Perform the following on one leg at a time.

Assembly

1. Remove the fork cap (1” wrench)

2. Turn upside down over a suitable pan and allow to drain.

3. Work the fork in and out several times.

4. Allow to drain at least 15 minutes.

5. Fill the leg with 118 ml (4 Oz) 5 wt fork oil.

1. Measure the fork oil level to the top of the fork tube with the leg collapsed,

and record for tuning purposes.

2. Install the fork spring.

3. Reconnect the damper rod to the fork cap (12 ft-lb, 16 Nm).

CAUTION:

The damper rod is hollow and will break if the nut is over tightened.

4. Reinstall the for cap into the fork leg (5 ft-lb, 6.7 Nm)

5. Reinstall the fork legs into the clamps (6 ft-lb, 8 Nm).

6. Reinstall the brake caliper.

6. Reinstall the front wheel (25 ft-lb, 34 Nm).

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Cobra DCX65 2003 Owner's And Service Manual

Brand: Cobra

Model: DCX65 2003

Category: Motorcycles

Type: Owner's And Service Manual

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Cobra DCX65 2003 Owner's And Service Manual

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