Cobra 2005 cm50 Service Manual

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Page 1

Page 2

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

MCCM2005.6

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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 CM50 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 OPER ATOR, 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 OPER ATED 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.

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Table Of Contents

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

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

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

Optional Components ........................................................................................ 7

Break-In Procedure ........................................................................................... 8

Starting Procedure ............................................................................................ 9

General Tips .................................................................................................... 10

Maintenance ....................................................................................................... 11

Schedule & Tips .............................................................................................. 11

Replacing Transmission / Clutch Lubricant ..................................................... 12

Chain adjustment ............................................................................................ 13

Front brake adjustment ................................................................................... 14

Rear brake adjustment .................................................................................... 15

Air Filter Cleaning ............................................................................................ 15

Fork Oil Replacement ...................................................................................... 16

Parts ................................................................................................................... 18

Parts – Airbox and Inlet System ...................................................................... 18

Parts – Bars and Controls ............................................................................... 19

Parts - Carburetor ............................................................................................ 20

Parts – Coolant System ................................................................................... 21

Parts – Electrical System ................................................................................ 22

Parts – Engine – Bottom End and Transmission ............................................. 23

Parts – Engine – Clutch and Kick Starter ..................................................... 24

Parts – Engine – Ignition and Water Pump .................................................. 25

Parts – Engine – Top End ............................................................................ 26

Parts – Exhaust System .................................................................................. 27

Parts – Forks & Triple Clamps ......................................................................... 28

Parts – Forks – Leg Assembly ..................................................................... 29

Parts – Frame – Mounting Hardware I ............................................................ 30

Parts – Frame – Mounting Hardware II ........................................................ 31

Parts - Frame – Mounting Hardware III ........................................................ 32

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Parts – Front Brakes ....................................................................................... 33

Parts – Front Wheel ........................................................................................ 34

Parts – Plastic Bodywork & Seat ..................................................................... 35

Parts – Rear Brake .......................................................................................... 36

Parts – Rear Wheel ......................................................................................... 37

Parts – Shock .................................................................................................. 38

Parts – Swingarm Assembly............................................................................ 39

Service ................................................................................................................ 40

Engine Service ................................................................................................ 40

Engine Removal .......................................................................................... 41

Complete Engine Disassembly Procedure .................................................. 42

Top End Disassembly Procedure ................................................................ 42

Splitting the Cases ....................................................................................... 43

Engine assembly ......................................................................................... 44

Clutch .............................................................................................................. 49

Ignition ............................................................................................................. 54

Cooling System ............................................................................................... 57

Fuel & Air System ............................................................................................ 60

Exhaust ........................................................................................................... 63

Wheels & Tires ................................................................................................ 64

Tuning ................................................................................................................. 65

Suspension ..................................................................................................... 65

Rear shock ................................................................................................... 67

Front Forks .................................................................................................. 67

Gearing ........................................................................................................... 68

Carburetion ..................................................................................................... 70

Troubleshooting .................................................................................................. 72

Index ................................................................................................................... 74

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General Information

Items

CM 50

Dimensions

Wheelbase

35.75” (908mm)

Wheel size

10” (254mm)

Seat height

23.9” (607 mm)

Engine

Type

2-stroke, single cylinder, reed valve

Cooling system

Liquid-cooled

Coolant

Liquid Performance Mini Coolant / Antifreeze

Displacement

49.8 cc

Bore and stroke

39 mm x 41.7 mm

Ignition system

Electronic, analogic advance

Spark plug

Champion 8339-1, 8332-1 hotter, 8904-1 colder

Gap

0.023” – 0.025” (0.58 – 0.64 mm)

Ignition timing

0.045” (1.14 mm) Before To Dead Center (BTDC)

Fuel type

High octane pump gasoline

Oil type

Cobra Venom 2-cycle Race Oil

Fuel / oil mix ratios

Between 32:1 and 40:1 (after engine Break-In)

Carburetion

14 mm Dell’Orto

Main Jet

Slow (Pilot) jet

Float Height

16mm + 0.5mm (0.63” + 0.020”)

Transmission

Speed / Clutch

Single / Cobra 3 shoe

Final drive ratio

13/38T or 14/38 T

Chain

420

Transmission / clutch oil type

Cobra Venom 3 Shoe Clutch Milk

Quantity

235 ml (8.0oz)

Specifications - General

RACE FUELS ARE NOT RECOMMENDED

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Chassis

Front tire

2.50 – 10

Pressure

15 psi minimum

Rear tire

2.75 – 10

Pressure

15 psi min. (20 psi for hard pack or rocky conditions)

Front fork

Marzocchi 32mm

Fork oil type

SAE 20 weight

Fork oil amount

200 ml (6.8 oz) oil change, 220 ml (7.4 oz) rebuild

Collapsed fork oil height

70 mm (2.75”) spring in, no spacer

Torque Value

Size & ft-lb

in-lb

Cylinder head nuts

M6 X 1.0

Crankcase bolts

M6 x 1.0

Spark plug

(SP)

M14 x 1.25

Stator bolts

2.1

2.8

M5 X 0.8

Stator cover bolts

1.7

2.3

M4 X 0.75

Clutch cover bolts

5.8

7.9

M6 X 1.0

Clutch nut

480

10 x 1.25*

Clutch bolts

170

M6 x 1.0

Engine mount bolts

265

M8 X 1.25

Swingarm Pivot

250

M14 X 2.0

Intake manifold bolts

4.6

6.2

M6 X 1.0

Ignition rotor nut

480

M10 x 1.25*

Rear Sprocket Bolts

216

M7 X 1.0

Rear shock mounts

480

M10 x 1.5

Axle nuts

300

M12 X 1.25

Specifications - Torque Values

Fastener

8.8 105 12

* Apply high strength thread locking agent when installing (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.

Remarks

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Optional Components

Weight of Rider (lb)

Fork Spring

Shock Spring

Less than 38 (light)

KCMZ0012A

SCMUOH04

38 – 45 (std)

KCMZ0012

SCMUOH05

46 to 55 (stiff)

KCMZ0012B

SCMU0H06

Damping Rate

Fork Valving

(right)

Fork Valving

(left)

Shock Valving

Soft (fast)

KCMZ0033A

KCMZ0032A

SCMUOH07

Standard

KCMZ0033

KCMZ0032

SCMUOH08

Hard (slow)

KCMZ0033B

KCMZ0032B

SCMUOH09

Call your dealer, or the factory, for details

• Carburetor jets

• Pre-filter for the airbox

• Sprockets

o Front o Rear

• Suspension Springs

• Suspension valving

Compression

• Tires

• Tubes or ‘Tire Balls’

(12 lb/in, 2.10 N/mm))

(14 lb/in, 2.45 N/mm))

(16 lb/in, 2.80 N/mm)

Rebound

(275 lb/in) red

(285 lb/in) yellow

(295 lb/in) white

(kit)

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Break-In Procedure

Your Cobra CM50 is a close-tolerance high performance machine an d break-in time is very important for maximum life and performance. The CM50 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 th e 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 sur e to use high octane pump gas with Cobra’s specially formulated Cobra Venom 2-cycle Race Oil. (Part # MCMUOL02)

CAUTION: Failure to use proper fuel, oil, or fuel/oil mixture 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.

• Start bike on stand

• First 5 minute period, operate the bike on the stand with a combination of idle

and high RPM operation. (avoid prolonged high RPM but spin the rear wheel good at least once or twice per minute)

• Allow bike to cool

• Ride for 15 minutes maximum (avoid prolonged high RPM operation and

avoid abusing the clutch with throttle blipping.

• Cool and inspect bike for loose fasteners.

• Next ½ hour of operation, 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.

• 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!

NOTE:

During break-in the bike will likely lose some engine c oolant through the radiator overflow hose. Losing up to 4 oz (120 ml, ½ cup) is normal. Proper coolant level will cover the top of the radiator cores. Removing the radiator cap and looking inside is the only way to check the coolant level.

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Never open the radiator cap of a machine that has a hot or warm engine or one that has recently been ridden. Burning and scalding could occur.

CAUTION: It is important that the radiator cap is installed correctly and completely otherwis e engine damage could occur.

Starting Procedure

Before starting the machine inspect the following:

• Make sure vehicle is properly maintained (see Schedule & Tips in the Maintenance section)

• Check the throttle for smooth operation and sound closing.

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

complete the distance required. (High octane pump gas with Cobra’s specially formulated Cobra Venom 2-cycle Race 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. Place the motorcycle on a stand of sufficient strength that positions the motorcycle in a level upright position with the rear wheel off the ground.

2. Pull up the choke knob and turn it to lock it.

3. Kick start the engine.

4. Rev the engine in short spurts, turning the throttle no more than 1/4 open until the engine will run without the choke.

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

6. 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.

This is a high performance race motorcycle. Too much application of throttle will likely land your little racer on his or her arse. Fenders can be replaced but bruised egos and other body parts take longer.

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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 foot brake 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. Cobra offers a carburetor inlet cover RCMU0109 to keep water and dirt

from getting into the carburetor when the bike is being washed.

7. New chains will stretch on first use. Never install a new chain prior to a

race. Always ‘break’ them in during practice.

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

The first two digits indicate the model and the seventh indicates the model year (MY).

a. Example, CMxxxx5xxx is a 2005 Model Year CM50.

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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 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 str ands of t he 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 ot her light oil. o Check drive chain for

 Proper tension and adjust if necessary.  Adequate lubrication and lubricate if necessary.

o Insure that the ignition s tator 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.

o Inspect the rear spr ocket dam per plate for bending or warping.

Straighten or replace if more than 1/16” (1.6 mm) from flat.

• 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. Because of the amount of heat generated by the clutch and engine during

extended periods of riding, it is advisable to remove the ignition cover afterward to allow the ignition to cool off. The heat transfers through the cases and can damage the stator as it cools off because of lack of airflow around the stator.

2. 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.

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Be sure the fuel tank and carburetor have been removed and safely located away from the welding process.

3. 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.

4. If your kick-starter lever does not return to the rubber bumper, use WD-40

or light penetrating oil under the plastic cover behind the spring on the shaft. The shaft is a very close fit to the case and also has an O-ring in it and is difficult to get lubrication to which may cause binding. If it does not loosen up, remove the kick-starter cover and kicking assembly. Grease the shaft.

Replacing Transmission / Clutch Lubr i cant

Tools needed:

• 225 ml (7.6 oz) Cobra Venom 3 Shoe Clutch Milk (Part # MCMUGF01).

• 13 mm combination wrench

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 is ‘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 a 13 mm wrench, remove

the oil drain bolt located on the right side of the engine, on the clutch cover, near the brake lever (Item 2, figure 1).

NOTE: You may need to adjust the brake pedal (up or down) to gain access to the drain bolt.

4. After it has drained, reinstall the bolt being sure that the copper gasket is in

place. Torque to 15 Nm (11 ft-lb).

Figure 1

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5. Reapply oil from oil fill plug 235 cc Cobra Venom 3 Shoe Clutch Milk thru the

fill plug.

NOTE:

Lean bike over onto it’s left hand side so that the clutch cover is up unless you have a squeeze bottle.

6. Reapply the oil fill bolt, hand tight, being sure the fiber gasket is in place.

CAUTION: Cobra has spent considerable time and money developing the proper lubr ication to handle the harsh environment of the automatic clutch and transmission of this motorcycle. Cobra’s specially developed Cobra Venom 3 Shoe Clutch Milk (Part # MCMUGF01) was formulated to provide superior lubrication and cooling capability over extended periods of time and is the recommended lubricant for your Cobra motorcycle.

Chain adjustment

Tools required for chain adjustment

• 19 mm wrench or socket

• 13 mm wrench or socket

1. Make sure that the rear wheel is

aligned properly.

2. For proper adjust ment, the chain

should have 35 mm (1 3/8”) free movement just behind the chain block with no load on the bike (figure 2)

Figure 2

CAUTION: Sit on the bike and verify that the chain has a minimum of 12mm (1/2”) free movement when the chain is at it’s tightest point.

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Figure 3, from the brake lever

Figure 4, from the brake hub

3. If the chain requires adjusting, loosen the axle with a 19 mm wrench and tighten the chain by rotating the adjustor bolts clockwise (CW) or loosen the chain by rotating the adjustor bolts (CCW).

4. Retighten the axel bolt to 25 ft-lb (34 Nm).

5. Retighten the adjustor bolt

Figure 3

CAUTION: Always check rear brake adjustment and free-play after adjusting the chain.

Front brake adjustment

Tools recommended for front brake maintenance:

• 10mm open end wrench

From the brake lever:

1. Slide the cover out of the way

2. Loosen the locking nut on the brake lever.

3. Adjust the bolt to desirable position.

4. Tighten the locking nut.

5. Slide the protective cover back over the lever pivot and adjustor

From the brake hub:

1. Loosen the 10mm nut on the hub.

2. Adjust the brake cable to desirable position

3. Tighten the 10mm nut. CAUTION:

If you tighten the front brake up too much, the brakes may hang up causing the brake pads to wear incorrectly and prematurely.

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Rear brake adjustment

Figure 5, adjust brake lever free hei ght

Figure 6, adjust brake lever ‘free pl ay’

Tools recommended for rear brake maintenance:

• 10mm open end wrench There are 2 adjustments on the brake.

From the brake lever:

6. Loosen the 10mm nut on the back of the brake pedal.

7. Adjust the bolt to desirable position

8. Tighten the 10mm nut.

From the brake hub:

1. Adjust the wing nut to the desirable position. CAUTION:

If you tighten the wing nut too much, the brakes may hang up. If so, the brake pads will burn up, and need to be replaced.

Air Filter Cleaning

Tools recommended for air filter maintenance:

• #2 Phillips head screwdriver

• 4 mm hex key (Allen)

• Foam filter oil

Procedure

1. Removed the seat with the 4 mm hex key

2. Remove the filter/air inlet boot from the back of the carburetor with a flat screwdriver

3. Pull the filter / boot assembly back, up, and out the top of the airbox.

4. Clean the filter in a nonflammable solvent to remove the filter oil.

Do not clean the air filter with gasoline or other highly volatile petr oleum product. 15

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Diesel fuel or kerosene would be preferred but caution should still be taken. Ho t soapy water works well.

5. Clean the filter in hot soapy water to remove all dirt particles.

6. Allow it to dry thoroughly.

7. Saturate with filter oil and remove excess.

NOTE:

The Cobra is equipped with a special designed Air box. It is very important to keep the air filter clean and properly oiled with high quality water-resist ant foam filter oil. It’s very important to oil your filter consistently each time because varied amounts of oil will change your carburetor jetting.

8. Reinstall the filter / boot assembly by pushing it down and forward into the airbox making sure the letters “CM” are visible between the carburetor and airbox (figure 8).

Figure 8

NOTE:

Make sure you change or clean your filter after each moto. We recommend carrying multiple filters in your toolbox, one for each practice session and moto.

Fork Oil Replacement

Tools required

• 5 & 6 mm Allen wrench

• 19 mm wrench or socket (two required)

• Spring clip remover

Disassembly 16

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1. Remove the front wheel.

2. Remove the fork legs from the triple clamps.

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

4. Using your hands, remove the black rubber plug from the top of the fork leg exposing the white plastic cap.

5. Secure the fork leg assembly in a vice by gripping the leg across the flats through which the axle bolt goes through.

6. Depress the white plastic cap inwards (down) and remove the wire spring clip from its groove.

7. Remove the white cap, the fork spring preload sleeve, and the fork spring.

NOTE: Depressing the fork leg will facilitate removing the white cap.

8. The fork can now be turned upside down and drained.

Assembly

1. Fill the leg with 200 cc (6.8 oz) 20 wt fork oil.

2. Standard fork oil level is 70 mm (2.75”) from the top edge with the fork collapsed.

NOTE: Remove the preload sleeve but leave the spring in for the measurement.

3. Install the preload sleeve.

4. Install and depress the white cap while installing the spring clip.

5. Fork may be reinstalled.

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Parts

Airbox and Inlet System

REF #

PART #

DESCRIPTION

ZCMU0032

GASKET – REED TO CYLINDER

ECKG0205

REED VALVE

ZCMU0031

GASKET – MANIFOLD TO REED

ECKG0203

INLET MANIFOLD

HCWF0601

6MM FLAT WASHER

HCBC0625

M6X25 SOCKET HEAD CAP SCREW

MCKGHO04

HOSE CLAMP – CARBURETOR TO MANIFOLD

RACM0002

CARBURETOR 14MM

Not Shown

FCMU0026

FUEL LINE

Not Shown

MCMUCL04

HOSE CLAMPS – FUEL LINE

FCMU0067

THROTTLE CABLE

RCCM1301

VELOCITY STACK

MCKGHO01

HOSE CLAMP – AIR BOOT TO CARBURETOR

RCMU0403

AIR FILTER WITH BOOT

RCMU0405

AIR BOX – CM

HCBB0612

M6X12 BUTTON HEAD BOLT (2 REQ’D)

RCMU1407

BRACKET – MUD FLAP

RCMU0406

MUD FLAP – CM

Parts – Airbox and Inlet System

Figure 7

Page 20

Parts – Bars and Controls

Bars and Controls

REF #

PART #

DESCRIPTION

FCMU0066

THROTTLE ASSEMBLY

FCMU0068

THROTTLE COVER

TCMU0008

GRIPS (SET OF TWO)

FCMU0067

THROTTLE CABLE

FCMU0033

KILL SWITCH ASSEMBLY

KCMZ0001

M8X50 SOCKET HEAD CAP SCREW (4 REQ’D)

KCMZ0003

LOWER HANDLE BAR CLAMP (2 REQ’D)

KCMZ0002

TOP HANDLE BAR CLAMP (2 REQ’D)

TCMU0019

HANDLEBAR - ALUMINUM

BCMU0100

BRAKE LEVER / PERCH ASSEMBLY WITH ADJUSTOR

BCMU0108

FRONT BRAKE CABLE

Figure 8

Page 21

REF. #

PART #

DESCRIPTION

RCCM0001

COMPLETE CARBURETOR 14MM

RCMU0305

CARB SLIDE

RCMU0601

NEEDLE

RCMU0002

ATOMIZER

RCMU0092

MAIN JET

CHOKE JET

RCMU0301

FLOAT

RCMU0102

RUBBER CABLE CAP SEAL

RCMU0003

CABLE ADJUSTOR

RCMU0006

TOP CARB SCREW

RCMU0106

CARB TOP

RCMU0012

DIFFUSER

RCCM1301

VELOCITY STACK – 05 style

RCCM0314

14MM CARB RESTRICTOR

Not Shown

FCMU0026

FUEL LINE

Not Shown

MCMUCL04

HOSE CLAMPS – FUEL LINE

Parts Carburetor

Figure 9

5 RCMU0055 PILOT JET

13 ZCMU0007 TOP CARB GASKET 14 RCMU0004 SLIDE SPRING 15 RCMU0205 NEEDLE RETA INER PLATE 16 RCMU0007 NEEDLE CLIP 17 RCMU0204 CHOKE ASS’Y. 2001 CM 20 RCMU0009 FUEL MIX TURE SC REW 21 RCMU0011 IDLE ADJUSTMENT SCREW 25 RCMU0103 FLOAT BOWL GASKET 26 RCMU0107 FLOAT NEEDLE

28 RCMU0016 FLOAT RETAINER PIN 29 RCMU0106 FLOAT BOWL 30

RCMU0201 BOTTOM FLOAT SCREW

Carburetor

Page 22

Parts – Coolant System

Coolant System

REF #

PART #

DESCRIPTION

ECMU0061

RADIATOR WITH CAP

MCMUHO02

RADIATOR HOSE LEFT

MCMUCL02

HOSE CLAMP

ECHA0003

MOUNTING BRACKET – RADIATOR BOTTOM

HCBC0607

M6X50 SOCKET HEAD CAP SCREW

HCNL0601

6MM LOCK NUT

MCKGGR00

GROMMET – RADIATOR MOUNTING

MCMUHO03

RADIATOR HOSE RIGHT

ECHA0002

VENT HOSE

ECHA0109

MOUNTING BRACKET – RADIATOR TOP

HCBC0660

M6X60 SOCKET HEAD CAP SCREW

Figure 10

Page 23

Parts – Electrical System

Electrical System

REF #

PART #

DESCRIPTION

IAMU0001

COIL W/SPARK PLUG CAP

ECMU0065

SPARK PLUG, CHAMPION (8339-1)

ECMU0067

OPTIONAL HOTTER PLUG (8332-1)

ECMU0066

OPTIONAL COLDER PLUG (8904-1)

FCMU0033

KILL SWITCH ASSEMBLY

HCBC0516

SCREW, M5 X 16 (2 PER)

HCCN0000

5MM CLIP NUT (2 PER)

IAMU0003

GROUND WIRE

HCWF0504

WASHER FOR STATOR (3 PER)

HCBC0525

5mm x 25 SOCKET HEAD CAP SCREW

HCBC0535

5mm x 35 SOCKET HEAD CAP SCREW (2 req’d)

HCNS1001

NUT 10MM

ECKG0042

PULLEY, WATERPUMP CRANK

ICMU0006

ROTOR

NOT SHOWN

ICMU0012

WOODRUFF KEY

ICMU0007

STATOR

NOT SHOWN

MCKGGR01

GROMMET - STATOR LEAD

Figure 6

Page 24

Parts – Engine – Bottom End and

Engine Bottom End and Transmission

REF #

PART #

DESCRIPTION

ECKG0017

CRANKCASE, IGNITION SIDE no bearings

ECMU0020L

BEARING, TRANSMISSION PRECISION

ECKG0004

SNAP RING, WATER PUMP

ZCMU0501

GASKET, CRANKCASE

ECMU0106

SECONDARY SHAFT, TRANSMISSION WITH GEAR

ECMU0017

SEAL, CRANKSHAFT

ECMU0016

BEARING, CRANKSHAFT

ECMU0001

BEARING, TRANMISSION SECONDARY SHAFT

ECMU0038

CRANKSHAFT

ECKGBR01

BEARING, TRANSMISSION OUTPUT SHAFT

ECDC0031

DOWEL, ENGINE CASE ALIGNEMENT

HCBH0805

M8X12 SCREW

HCWC0000

COPPER GASKET

ECMU0107

OUTPUT SHAFT, TRANSMISSION WITH GEAR

ECMU0020

BEARING, TRANSMISSION PRECISION

ECKG0018

CRANKCASE, CLUTCH SIDE, no berings

HCBH0612

M6X12 HEX HEAD SCREW - BEARING RETAINER

HCWL0601

6MM LOCK WASHER

Transmission

Figure 7A

Page 25

Parts –

Engine – Clutch and Kick Starter

REF #

PART #

DESCRIPTION

ECMU0027

CLUTCH COVER COMPLETE WITH KICK LEVER

ZCMU0030

CLUTCH COVER GASKET

ECMU0207

KICKSTART GEAR SMALL

HCBC0608

M6X55 SHCS CLUTCH CVR SCREW LN G (2 REQ’D) CENTER

HCBC0606

M6X45 SHCS CLUTCH COVER SCREW SHORT (4 REQ’D)

ECMU0037

OIL FILL PLUG

ZCMU0001

OIL FILL PLUG GASKET

HCBH0805

M8X12 OIL DRAIN SCREW

HCWC0000

COPPER GASKET

ECMU0202

LEVER – KICK START

ECMU0205

RUBBER – KICK START LEVER

ECMU0204

KICK START DUST COVER

ECMU0403

SPRING – KICK LEVER

CCMU0031

CLUTCH ARBOR

CAKG0005

CLUTCH SHOE (SET OF 3)

NOT SHOWN

CAKG0004

SET OF 3 CLUTCH SHOES WITH SPRINGS, WASHER & BOLT

NOT SHOWN

CAKG0002

CLUTCH ASSY W/ ARBOR, SHOES, SPRINGS, WSHR & BOLT

CCMU0129

SPRING, CLUTCH (SINGLE PIECE)

HCWS0801

WASHER, CLUTCH (SINGLE PIECE)

NOT SHOWN

CAMU0008

SPRINGS, WASHER, & BOLT (COMPLETE SET FOR 3 SHOES)

HCBS5603

BOLT, CLUTCH CENTER (SINGLE PIECE)

ECMU0018

NUT, CLUTCH SPECIAL

ECMU0133

CLUTCH BASKET WELDED WITH BUSHING

ECMU0003

BUSHING, CLUTCH BASKET

ECMU0040

SPACER, CLUTCH BASKET (1 - 3 REQ’D)

ECMU0132

COOLANT FITTING

ECMU0108

GEAR, PRIMARY TRANSMISSION

HCNS1202

NUT, 1/2-20 LEFT HAND THREAD

ECMU0503

FITTING, CASE VENT

NOT SHOWN

ECMU0504

HOSE – CRANKCASE VENT

ECMUSP01

KICK START DOG SPRING (PAPER CLIP)

HCWB0042

SPRING WASHER

Engine – Clutch and Kick Starter

Figure 13

Page 26

Parts –

Engine – Ignition and Water Pump

REF #

PART #

DESCRIPTION

ECKG0001

IGNITION COVER

ZCKG0101

IGNITION COVER GASKET

HCBC0445

M4 x 45 SOCKET HEAD (4 REQ’D)

ECKG0170

WATER PUMP BELT

ECKG0175

WATER PUMP PULLEY, FAN TYPE - DRIVEN

ECMU0180

BELT RETAINER

HCBS0003

SHOULDER BOLT 6MM

HCWF0501

FLAT WASHER

ECKG0072

BEARING, WATER PUMP

ECKG0142

SHAFT, WATER PUMP

ECKG0074

SEAL, WATER PUMP SHAFT

ECKG0073

IMPELLER, WATER PUMP

HCBB0001

IMPELLER SCREW, SHCS 10-32X1/2

HCBC0408

M4mm x 8 SOCKET HEAD black oxide

CASE SCREW, SHCS M6X55 (1 REQ’D)

CASE SCREW, SHCS M6X45 (2 REQ’D)

CASE SCREW, SHCS M6X40 (6 REQ’D)

HCWF0504

WASHER FOR STATOR (3 PER)

ICMU0007

STATOR

HCBC0535

5mm x 35 SOCKET HEAD CAP SCREW (2 req’d)

HCBC0525

5mm x 25 SOCKET HEAD CAP SCREW

ICMU0006

ROTOR

ECKG0042

WATER PUMP PULLEY, CRANK

HCNS1001

NUT 10MM

MCKGGR00

GROMMET

PCKG0014

SPROCKET, 14T COUNTERSHAFT

ECKGSR03

SNAP RING, COUNTERSHAFT SPROCKET

ECMU0073

SPACER, SPROCKET

ECMU0072

SEAL, COUNTERSHAFT

ZCDCOR01

O-RING, COUNTERSHAFT SPACER

ECKG0004

RETAINER, WATER PUMP ASSEMBLY

ICMU0012

WOODRUFF KEY – FLYWHEEL / CRANKSHAFT

4mm washer

Holder – vent hose

Engine – Ignition and Water Pump

Figure 7C

Page 27

Parts –

Engine – Top End

REF #

PART #

DESCRIPTION

ECKG0041

CYLINDER

ZCKG0501

BASE GASKET

ECMU0043

PISTON KIT

ECMU0055

PISTON RINGS (2 PER SET)

ECMUSR00

SNAP RING FOR PISTON (2 REQ'D)

ECKG0012

WRIST PIN

ECMU0077

BEARING, WRIST PIN

ZCMUOR07

O-RING, EXHAUST FLANGE

ECMU0086

EXHAUST FLANGE

NOT

SHOWN

ZCMOTE11

O-RINGS – PIPE TO FLANGE (2 REQ’D)

HCBC0602

M6X20, EXHAUST FLANGE SCREW (2 REQ'D)

HCNS1401

NUT, CYLINDER HEAD 1/4-20 (4 REQ'D)

HCWF1401

FLAT WASHER, 1/4" (4 REQ'D)

ECKG0026

CYLINDER HEAD OUTER

ZCMUOR02

O-RING, CYLINDER HEAD LARGE

ZCMUOR08

O-RING CYLINDER HEAD SMALL

ZCMUOR03

O-RING CYLINDER STUD (8 REQ'D)

ECKG1121

CYLINDER HEAD, INSERT

ZCMUOR05

O-RING CYLINDER HEAD MEDIUM

ECMU0075

STUD, CYLINDER 6MM

Engine – Top End

Figure 15

Page 28

Parts – Exhaust System

Exhaust System

REF #

PART #

DESCRIPTION

XCCM2004

2004 CM EXHAUST PIPE

ZCMUOR30

HEADER PIPE O-RINGS (2 REQ’D)

XCMU0005

EXHAUST SPRING - SHORT

MCMUGR06

PIPE GROMMET MALE

MCMUGR07

PIPE GROMMET FEMALE

MCMUSP02

PIPE GROMMET SPACER

HCWF1478

PIPE GROMMET WASHER

HCBF0635

M6X35 FLANGE HEAD BOLT

XCKG0009

PIPE / SILENCER SEAL

XCKG0003

SILENCER

NOT SHOWN

XCMU0018

SILENCER PACKING

HCBF0630

M6X30 FLANGE HEAD BOLT

MCMUGR04

GROMMET – SILENCER MOUNTING (2 REQ’D)

Figure 16

Page 29

Parts – Forks & Triple Clamps

Front Forks and Triple Clamp

REF #

PART #

DESCRIPTION

KCMZ0029

OUTER FORK LEG – RIGHT (NON BRAKE) SIDE

NOT SHOWN

KCMZ0131

OUTER FORK LEG ASSY – RIGHT WITH SEAL & SWIPER

KCMZ0020

OUTER FORK LEG – LEFT (BRAKE) SIDE

NOT SHOWN

KCMZ0121

OUTER FORK LEG ASSY – LEFT WITH SEAL & SWIPER

KCMZ0026

INNER FORK LEG – RIGHT (COMPRESSION) SIDE

KCMZ0027

INNER FORK LEG – LEFT (REBOUND) SIDE

HCCC0001

CLAMP – BRAKE CABLE

HCBC0502

M5X20 SOCKET HEAD CAP SCREW

HCNL0501

5MM LOCK NUT

HCBF0616

FENDER BOLT, M6X16 FLANGE HEAD (4 REQ’D)

KCMZ0025

TRIPLE CLAMP – LOWER WITH STEM

HCBC0625

M6X25 SOCKET HEAD CAP SCREW (4 REQ’D)

KCMZ0005

TRIPLE CLAMP – UPPER (NO BAR MOUNTS)

HCBC0806

M8X30 SOCKET HEAD CAP SCREW (2 REQ’D)

KCMZ0003

BAR MOUNT – LOWER (2 REQ’D)

KCMZ0002

BAR MOUNT – UPPER (2 REQ’D)

KCMZ0001

M8X50 SOCKET HEAD CAP SCREW

HCNJ0101

STEERING HEAD NUT 1X14

FCMU0004

STEERING HEAD BEARING (2 REQ’D)

FCMU0103

DUST COVER (2 REQ’D)

BCMU0007

BRAKE STOP

HCBH0808

M8X30 BUTTON HEAD SCREW

Figure 17

Page 30

Parts –

REF #

PART #

DESCRIPTION

KCMZ0004

FORK PLUG – BLACK

KCMZ0007

SNAP RING FOR FORK CAP

KCMZ0008

INNER FORK CAP - WHITE

KCMZ0009

O-RING UNDER FORK CAP

KCMZ0111

PRELOAD SLEEVE

KCMZ0012

FORK SPRING

KCMZ0013

SWIPER

KCMZ0014

SNAP RING

KCMZ0015

FORK SEAL

KCMZ0016

WASHER

KCMZ0017

SEALING RING FOR REBOUND PISTON

KCMZ0118

PISTON ROD - REBOUND

18A

KCMZ0118A

PISTON ROD - COMPRESSION

KCMZ0019

REBOUND SPRING

KCMZ0020

FORK LEG OUTER LEFT

KCMZ0021

FORK LEG – 5 PIECE UNIT – LEFT

HCWC0000

WASHER

HCBC0806

8 X 30 CS

KCMZ0026

FORK TUBE – INNER RIGHT

KCMZ0027

FORK TUBE – INNER LEFT

KCMZ0028

TOP OUT BUMPER

KCMZ0029

FORK LEG – OUTER RIGHT

KCMZ0031

FORK LEG – 5 PIECE UNIT – RIGHT

HCBC0609

6 X 20 CS

Forks – Leg Assembly

Figure 18

Page 31

Parts – Frame – Mounting Hardwar e I

Frame – Engine, Tank, and Pipe Mounts, Brake Snake

REF #

PART #

DESCRIPTION

FAMU0004

FRAME 2004 CM50

HCBH1403

SWINGARM BOLT

HCNL1402

SWINGARM LOCK NUT (M14X1)

HCBH0880

M8X80 SOCKET HEAD CAP SCREW

HCNL0801

8MM LOCKNUT

MCMUGR06

PIPE GROMMET MALE

MCMUGR07

PIPE GROMMET FEMALE

MCMUSP02

PIPE GROMMET SPACER

HCWF1478

PIPE GROMMET WASHER

HCHA0003

6MM CLIPNUT

BCMU0008

CABLE – BRAKE SNAKE

BCMU0009

CRIMP – BRAKE SNAKE

HCBF0635

M6X35 FLANGE HEAD BOLT

TCHA0004

BUSHING – REAR TANK MOUNTING

HCNL0601

6MM LOCKNUT

TCHA0006

BUSHING – FRONT TANK MOUNT (2 REQ’D)

HCBF0685

M6X85 SHCS

Figure 19

Page 32

Parts – Frame – Mounting Hardware II

Frame – Seat, Fender, Right Side Panel, Brake Pedal, Silencer & Shock Mounts

REF #

PART #

DESCRIPTION

FAMU0004

FRAME 2004 CM50

HCBB0635

M6X35 BUTTON HEAD CAP SCREW

HCHA0003

6MM CLIPNUT

HCBF0620

M6X20 FLANGE HEAD BOLT

HCNF0602

6MM NYLOC FLANGE NUT

HCBF0630

M6X30 FLANGE HEAD BOLT

MCMUGR04

GROMMET – SILENCER (2 REQ’D)

HCBF0616

M6X16 FLANGE HEAD BOLT

HCBB0803

M8X40 BUTTON HEAD SCREW

HCNL0801

8MM LOCK NUT

HCBC1001

M10X45 SOCKET HEAD CAP SCREW

Figure 20

Page 33

Parts - Frame – Mounting Hardware III

Frame – Radiator, Footpeg, Chain Roller, and Airbox Mounts

REF #

PART #

DESCRIPTION

FAMU0004

FRAME 2004 CM50

ECHA0003

MOUNTING BRACKET – RADIATOR BOTTOM

HCBC0607

M6X50 SOCKET HEAD CAP SCREW

HCNL0601

6MM LOCK NUT

MCKGGR00

GROMMET – RADIATOR MOUNT (2 REQ’D ON BOTTOM, 1 ON TOP BRACKET)

ECHA0109

MOUNTING BRACKET – RADIATOR TOP

HCBC0660

M6X60 SOCKET HEAD CAP SCREW

FCMU0057

CHAIN ROLLER

HCWF1201

WASHER FLAT, CHAIN ROLLER (2 REQ’D)

HCCP0002

COTTERPIN 3/32 X 1 (2 REQ’D)

TCMU0014

FOOTPEGS (SET OF 2)

TCMU0102

SPRINGS – FOOTPEG (SET OF 2)

HCBF0850

M8X50 FLANGE HEAD BOLT

HCWF5601

FLAT WASHER

HCNL0801

8MM LOCK NUT

HCBF0616

M6X16 FLANGE HEAD BOLT

Figure 21

Page 34

Parts – Front Brakes

Front Brakes

REF #

PART #

DESCRIPTION

BCMU0300

BRAKE HUB – FRONT

BCMU0113

BRAKE ARM – FRONT

BCMU0005

CABLE CLAMP, WASHER & NUT

BCMU0006

CABLE ADJUSTOR

BCMU0110

BRAKE SHOE (PAIR)

BCMU0010

SPRING – BRAKE RETURN

BCMU0011

PUSH NUT – BRAKE SPRING (2 REQ’D)

BCMU0007

BRAKE STOP

HCBH0808

M8X30 BUTTON HEAD SCREW

BCMU0100

BRAKE LEVER / PERCH ASSEMBLY WITH ADJUSTOR

BCMU0108

BRAKE CABLE

Figure 22

Page 35

Parts – Front Wheel

Front Wheel

REF #

PART #

DESCRIPTION

WAMU0300

FRONT WHEEL COMPLETE

WCMU0250

FRONT TIRE 10X2.50”

WCMUTU10

TUBE 10”

WCMU0014

FRONT AXLE

HCWF1202

WASHER – AXLE

WCMU0023

FRONT WHEEL SPACER

WCMU0020

BEARING – WHEEL (2 REQ’D)

WCMU0004

SPACER – WHEEL FRONT

BCMU0300

BRAKE HUB – FRONT

HCNS1201

NUT - AXLE

Figure 23

Page 36

Parts – Plastic Bodywork & Seat

Plastic and Seat

REF #

PART #

DESCRIPTION

NOT SHOWN

TCMU0020

GRAPHIC KIT

TCHA0107

FRONT FENDER

NOT SHOWN

HCBF0616

FENDER BOLT, M6X16 FLANGE HEAD (4 REQ’D)

TCMU0005

NUMBER PLATE - FRONT

NOT SHOWN

HCBF0625

M6X25 FLANGE HEAD BOLT – FRONT NUMBER PLATE MOUNT

TCHA0008

RADIATOR SHROUD - RIGHT

TCHA0009

RADIATOR SHROUD - LEFT

MCMUBC01

BUNGEE CORD – SHROUD HOLDING

TCHA0001

FUEL TANK – NOT COMPLETE

NOT SHOWN

TCHA0002

CAP – FUEL TANK

NOT SHOWN

TCHA0003

HOSE – FUEL CAP

NOT SHOWN

HCSF0620

M6X20 PHILIPS HEAD SCREW – SEAT & SHROUD HOLD

NOT SHOWN

TCHA0005

SPACER – SEAT & SHROUD HOLD

NOT SHOWN

TCHA0006

SPACER – FRONT TANK MOUNT (2 REQ’D)

NOT SHOWN

HCBC0685

M6X85 SHCS – FRONT TANK MOUNT

NOT SHOWN

HCNL0601

6MM LOCK NUT – FRONT TANK MOUNT BOLT

NOT SHOWN

HCBC0645

M6X45 SOCKET HEAD CAP SCREW

NOT SHOWN

TCHA0004

BUSHING – REAR TANK MOUNTING

TCMU0038

FUEL PETCOCK

Not Shown

FCMU0026

FUEL LINE

Not Shown

MCMUCL04

HOSE CLAMPS – FUEL LINE

TCHO0001

SEAT

NOT SHOWN

HCBB0635

M6X35 BUTTON HEAD CAP SCREW – SEAT HOLDING

TCHA0011

NUMBER PLATE – LEFT REAR

NOT SHOWN

HCBF0616

M6X16 FLANGE HEAD BOLT – FRONT SECURE

NOT SHOWN

HCBF0620

M6X20 FLANGE HEAD BOLT – FENDER & REAR SECURE

NOT SHOWN

HCNF0602

6MM NYLOC FLANGE NUT

TCHA0010

NUMBER PLATE – RIGHT REAR

NOT SHOWN

HCBF0616

M6X16 FLANGE HEAD BOLT – FRONT SECURE

NOT SHOWN

HCBF0620

M6X20 FLANGE HEAD BOLT – FENDER & REAR SECURE

NOT SHOWN

HCNF0602

6MM NYLOC FLANGE NUT

TCHA0012

FENDER – REAR

NOT SHOWN

HCBF0616

M6X16 FLANGE HEAD BOLT – FENDER & AIRBOX SECURE

Figure 24

Page 37

Parts – Rear Brake

Rear Brake System

REF #

PART #

DESCRIPTION

BAMU0301

BRAKE PEDAL

BCMU0008

CABLE – BRAKE SNAKE

BCMU0009

CRIMP – BRAKE SNAKE

HCBB0803

M8X40 BUTTON HEAD SCREW

HCNL0801

8MM LOCK NUT

HCBH0602

M6X25 HEX HEAD BOLT (BRAKE STOP ADJUST)

HCNS0601

6MM NUT

BCCM0105

BRAKE ROD

BCMU0111

BRAKE ROD BARREL

HCNW0001

BRAKEROD WINGNUT

BCMU0109

BRAKE HUB - REAR

BCMU0112

BRAKE ARM – REAR

BCMU0010

SPRING – BRAKE RETURN

BCMU0110

BRAKE SHOE (PAIR)

BCMU0011

PUSH NUT – BRAKE SECURE (2 REQ’D)

HCCP0001

COTTER PIN - 3/32 X 1/2

HCWF0502

5MM FLAT WASHER

Figure 25

Page 38

Parts – Rear Wheel

Rear Wheel

REF #

PART #

DESCRIPTION

WACM0100

WHEEL COMPLETE – REAR

WCMU0275

TIRE – REAR 10X2.75”

WCMUTU10

TUBE – 10”

PCMU0137

SPROCKET – 37T

PCMU0059

RUBBER SPROCKET DAMPERS

NOT SHOWN

WCMU0006

SPACER – SPROCKET DAMPER

WCMU0016

REAR AXLE

HCPA0002

AXLE HEAD FIXING PLATE

WCMU0001

REAR WHEEL SPACER (SPROCKET SIDE)

WCMU0020

WHEEL BEARING (2 REQ’D)

WCMU0003

WHEEL BEARING SPACER - REAR

BCMU0109

BRAKE HUB - REAR

WCMU0009

REAR WHEEL SPACER (BRAKE SIDE)

HCWF1202

WASHER – AXLE

HCNS1201

NUT – AXLE

WCMU0008

WHEEL DAMPER PLATE

HCBH0701

M7X35 HEX HEAD BOLT

PCCM0001

420

PCMU0001

MASTER LINK – 420 CHAIN

Figure 26

Page 39

Parts – Shock

REAR SHOCK

REF#

PART #

DESCRIPTION

SACM2004

SHOCK ABSORBER

SCMUOH05

SPRING – STANDARD (285 lb/in)

SCMUOH04

SPRING – LIGHT (275 lb/in)

SCMUOH06

SPRING – HEAVY (295 lb/in)

HCBC1001

M10X45 SHCS

Figure 27

Page 40

Parts – Swingarm Assembly

Swingarm

REF #

PART #

DESCRIPTION

GACM2004

SWINGARM ASSEMBLY (CONTAINS ITEMS 1 - 13)

GAMU0004

SWINGARM

GCMU0001

SWINGARM BUSHING (SINGLE PIECE)

GCMU0009

SPACER - PIVOT TUBE

GCMU0017

CHAIN GUARD

HCFH0516

M5X16 FLAT HEAD SCREW

HCWF0501

5MM FLAT WASHER

HCNL0501

5MM LOCK NUT

HCBF0620

M6X20 FLANGE HEAD BOLT (2 REQ’D)

PAKG0001

CHAIN GUIDE – ASSEMBLY COMPLETE

PCKG0004

CHAIN GUIDE - BOTTOM SLIDER

HCBFT640

M6 X 40 FLAT HEAD BOLT

HCNL0601

6MM LOCKNUT

FAMU0005

WHEEL PULL ASSEMBLY

FCMU0203

WHEEL PULL

FCMU0202

WHEEL PULL ENDCAP

HCWF5601

5/16” FLAT WASHER

HCBH0810

M8X65 HEX HEAD BOLT (FULL THREAD)

HCBH1403

SWINGARM PIVOT BOLT

HCNL1402

14MM LOCK NUT

HCBC1001

M10X45 SOCKET HEAD CAP SCREW

WCMU0016

AXLE BOLT

HCPA0002

AXLE HEAD FIXING PLATE

HCNS1201

12MM LOCKNUT

Figure 34

Page 41

Service

Trained technicians with precision gauging and proper assembly fixtures carefully assemble all Cobra engines to specific clearances. If you feel you have the skills, and the appropriate tools, to perform the following service tasks please f ollow the instructions closely. The part numbers are listed throughout to help you when ordering parts from your local Cobra dealer.

If you don’t feel comfortable with the service work, simply take your engine out of the frame and sent it to:

Cobra Precision Engines

11511 Springfield Road

North Lima, Ohio 44452

Cobra has specialized mechanics that will go through the entire engine, r epla cin g gaskets, bolts, any old part that is worn. The engine will be rebuilt using the same precision gauging and assembly fixtures as when it was assembled new. Before leaving, the engines performance will be measured on a dynamometer to ensure that your engine is operating at its highest potential. All this for one low nominal fee. Call (330) 549-9603 for details.

Engine Service

One method for determining whether the top end of your engine needs re built is to perform a WOT (Wide Open Throttle) kicking compression test. Before performing the procedure please read the caution notes below.

CAUTION:

• There appears to be a wide range of variability in reading compression gauges across the country.

• The head volume of this Cobra Motorcycle is very small and so req uir es many kicks ~20 before you establish the most accurate reading possible.

• Because of the geometry of the spark plug used in this Cobra M otorcycle, the adapter used with your compression tester must have a similar volume protruding into the combustion chamber to establish an accurate value.

• Length of hose on the compression tester will affect the reading. The short er the hose length the more accurate your reading will be.

Because of these difficulties in measuring an absolute compression value, a useful relative value can be achieved by testing your bike’s compression with your own particular gauge after a new top end or when the bike is new so t hat you know what your particular gauge reads on a ‘fresh’ engine. When it has

Page 42

dropped to 90% of its original value the engine will be down on power and would

Engine is Fresh

Measured Value

Engine Down on Power

Measured Value * 0.9

Engine NEEDS Rebuilt

Measured Value * 0.8

Example

110 psi

110 psi * 0.9 = 99 psi

110 psi * 0.8 = 88 psi

Your Values

benefit from a rebuild. When it’s dropped to 80% it really needs rebuilt! Using the table below will help you determine monitor the condition of your top end.

Procedure for Compression Testing

1. Shut off the fuel petcock.

2. Install the compression gauge into the spark plug hole.

3. Hold the throttle to wide open, and kick repeatedly (approximately 20

times) or until the gauge reading does not increase in value with each kick.

Engine Removal

To service the bottom end and transmission, the engine must be removed from the frame.

Tools required

• 10, 11, 13, 22 mm wrench

• 10, 14, 17 & 19 mm sockets

• 3,4 & 5 mm hex key (Allen wrench)

• 7 mm nut driver, flat or Phillip, screwdriver for hose clamps

• Spring remover

• Flywheel / clutch (Universal) puller (#MCMUTL68)

• Clutch nut removal tool (Call local dealer for details).

Procedure

1. Remove the seat (4mm hex key).

2. Turn of the fuel at the petcock and disconnect the fuel line.

3. Remove the tank (5 mm hex key & 10 mm socket).

4. Remove the carburetor from the inlet (flat head or Phillips head

screwdriver, 7 mm nut driver).

5. Remove the silencer & pipe (spring remover, 8 mm socket).

6. Disconnect the ground wire from the cylinder head (11 mm wrench).

7. Leaving the coolant lines connected to the engine, remove the radiator

from the frame (5mm hex with 10 mm wrench).

8. Remove the master link from the chain.

9. Remove front engine mount bolt (13 mm socket, 6 mm hex key).

10. Remove the swingarm bolt (22mm s ock et ).

Page 43

NOTE: Only drive the swingarm bolt far enough to clear the engine, leave it

holding the one side of the swingarm to the frame

11. Remove the engine from the right side of the fr ame.

12. Locate a suitable container for t he engine coolant and remove radiator

hoses from engine (coolant will drain).

NOTE: If the coolant looks to be free of contaminates it may be reused.

NOTE: If you are merely performing a top end service skip ahead to Top End

Disassembly Procedure.

Complete Engine Disassembly Procedure

1. Remove the magneto cover (3mm hex key)

2. Remove the bolt from the water pump shaft (3&4mm hex key) and slide off

the belt cover and the water pump belt

3. Using a flywheel holding tool and 14 mm socket remove the nut that

secures the flywheel.

4. Using the Cobra flywheel / clutch puller (#MCMUTL68), remove the

flywheel from the crankshaft.

5. Remove the stator (4mm hex key).

6. Remove the clutch nut / starter gear that holds on the clutch (special tool

available, contact your local dealer).

7. With the Cobra flywheel / clutch puller (#MCMUTL68), remove the clutch

from the crankshaft (details in Clutch Service portion of this manual).

Top End Disassembly Procedure

1. Remove the cylinder head nuts (11mm).

2. Remove the outer cylinder head.

3. Remove the cylinder head insert.

Page 44

INSPECTION NOTE:

Inspect the cylinder head for deposits and abrasions.

1. If there are deposits they should be removed a. Black oily deposits (indicating a rich mixture or improper oil

type/quantity) can be removed with solvent

b. Crusty deposits (indicating dirt ingestion) can be removed with

solvent and may require some scraping.

2. Abrasions a. Pitting or erosion indicates detonation and may require cylinder

head replacement, also

i. Retard the ignition timing

ii. Use a higher octane fuel

b. Missing chunks or indentations indicate broken hardware or

ingested items - replace the cylinder head.

4. Remove the cylinder.

Inspect the cylinder bore for abrasions, deposits, and missing coating.

1. If abrasions: scrapes, scratches, pitting, etc… are found, replace the

cylinder.

2. If deposits are all are found a. Clean with muratic acid. b. Once the deposits are removed, inspect for abrasions and missing

surface coating.

i. If there are abrasions or m issing coating, replace.

ii. If all looks well, the cylinder may be saved.

Muratic acid can be dangerous. Follow the manufacturers instructions closely.

5. Remove the piston clip with a scribe.

6. Remove the piston pin with a piston pin remover.

INSPECTION NOTE: Inspect the piston for abrasions and deposits on the top and sides and clean or replace as necessary.

Splitting the Cases

1. Remove the fasteners holding the two halves of the crankcase together.

2. Separate the cases with a proper case splitting tool.

Page 45

CAUTION: Take caution when handling the crankshaft. It is the main po wer transfer to the rest of the engine. If it is out of alignment, it will cause premature failure of your bearings which can lead to serious damage to the cylinder and the rest of the engine. Do not try to true the crank yourself. Truing the crank should be done professionally.

CAUTION:

• If you split the cases, check the gear tooth faces for chipping & signs of fatigue.

• Check the small needle bearings for fatigue. If the bearings are damaged, the engine cases should be checked to make sure the needle-bea ring casing didn’t oblong the bearing hole in the case.

• Needle bearings should be replaced every racing season.

Engine assembly

CAUTION: For any seals that are to be installed, apply a light amount of grease to the seals’ ID, assembly lube on all bearings and a small amount of Loctite to the OD.

1. Press the three bearings into the respective holes in each case half.

2. Press in the crank seals such that the concave side faces the crank weights.

3. Press in the counter shaft seal (concave side faces inside of transmission)

4. Install the water pump assembly wire ring retainer

5. Press in the water pump assembly

6. Tap both ways axially then verify easy rotation.

7. Inspect the crankshaft for proper true geometry (no more than 0.002 “,

0.05mm, measured at bearing journal area while supported from the ends).

8. Press crank into right case half

CAUTION: Insert a 7.05mm (0.278”) shim between the crank throws before pressing on the crank.

9. Insert the transmission input shaft and install large drive gear as shown in figures 25 & 26.

NOTE:

If the nut was removed from the input shaft, it will be easier to install and tighten later.

Page 46

Figure 25

Figure 26

Page 47

10. Insert dowel pins in the left side cas e as s hown in figur e 27.

Figure 8

11. Clean the gasket mating sur f ac es with acetone

12. Apply gasket sealer (ThreeBond 1104 gasket material or equivalent) to the mating surfaces of both crankcase halves).

NOTE: Gasket material is only required around the crankcase, and not the transmission.

13. Apply the crankcase gasket to the left crank case half being sure to install the gasket behind the connecting rod.

14. Assemble the two case halves together with the shim installed between the crank throws. Be sure to remove the shim after assembly.

15. Insert the screws with the proper lengt hs at locations shown.

Page 48

Figure 28

16. Torque to 12 Nm (105 in-lb) in the pattern shown in figure 28.

17. Trim away any excess gasket material.

NOTE: Check engine mount holes for excess material that may cause problems in engine installation.

18. Install the piston with new wrist pin bearing and, pin and clips.

CAUTION: Be sure to align the piston such that the arrow on the top piston surface points to the exhaust (front of bike/engine) and put assembly lube on the connecting rod bearing.

19. Install the piston rings.

CAUTION: Ring end gap should be no less than 0.25 mm (0.010”) and no more than

0.64mm (0.025”)

20. Install the base gasket.

21. Apply gasket sealer to the top surface of the gasket in the same locations indicated in figure 29.

22. Install the cylinder bein g sure that the piston rings are properly aligned with the indexing pins.

CAUTION: Never force the cylinder. If resistance is felt, determine the problem and solve it. Once installed slightly rotate the cylinder back and forth insuring that the rings are properly seated.

23. Install the cylinder st uds and o-rings as shown in figure 30.

Page 49

Figure 30

24. Install cylinder head inser t.

NOTE: A light application of silicone grease can help hold the o-rings into position during assembly.

25. Pressure test the engine insuring an acceptable leak down rate.

26. Install O-rings as shown in figure 31.

Figure 31

27. Install the cylinder head.

28. Install the washers (with flat s ide down) and nuts. Torque to 105 in-lb (12 Nm)

29. Secure the ground strap to the back left cylinder stud with an additional nut.

30. Install reed and inlet manifold with new gask et s ( 105 in-lb, 12 Nm) applying 1104 gasket sealer to both sides of all gaskets.

31. Leak check the engine to 20 ps i to ensure proper seal.

32. Install stator reinst allin g the grommet and wires (snug the bolts).

33. Install the rotor per Rotor Installation section, under the S3: Ignition portion of this manual.

34. Install the water pump outlet pipe ( apply Ult r a black Hi-Tem p RTV silic on gasket maker to the threads before assembly) before installing the clutch and rotate to a vertical position with the engine resting on a bench

35. Install the clutch per Clutch I nstallation section in this manual.

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36. Install the coolant drain plug with copper washer (11 ft-lb, 15 Nm).

37. Make sure that the exhaust spacer is on t he cylinder (53 in-lb, 6 Nm).

38. Install the spark plug with a f resh gasket (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).

Clutch

Cobra clutch puller assembly:

Clutch puller diagram

Figure 36

Tools recommended for clutch service:

• Universal clutch puller- a universal puller that pulls the clutch, main drive gear and rotor. (Part # MCMUTL70).

• 5mm T-handle

• Clutch nut removal tool (Call local dealer for details)

• Cobra 3 Shoe Clutch Milk (Part # MCMUGF01)

CLUTCH REMOVAL:

1. Drain the engine transmission oil.

2. Remove the pipe and remove the 6 bolts that hold the kick-starter cover on.

3. Remove the clutch nut (not left hand thread) on the end of the crankshaft with the clutch nut removal tool.

4. Attach the COBRA CLUTCH PULLER. There are three 6mm clutch puller holes located on the ends of the center hub. (figures 32 & 33) You mus t use a draw type puller to remove the clutch.

CAUTION:

Figure 37

Page 51

Do not use a j aw type puller or use the 6mm tapped h oles as jackscrews or you

CLUTCH ASSEMBLY REFERENCE DRAWING

REF #

PART #

DESCRIPTION

CAKG0004

Set of three shoes, springs, bolts, flat washers & nuts

CAMU0008

Set Of three springs, washers, bolts & nuts

CAKG0005

Set of three shoes

HCBS5603

Single center shoulder bolt

are likely damage the clutch or drum.

5. If necessary apply heat to the center clutch hub.

CAUTION: Do not heat the crankshaft threads or the aluminum shoes.

6. Keep tension on the puller as you are heating it.

The clutch will often pop off under tension from the puller and it will be very hot.

CLUTCH WASHER STACKUPS:

Once the clutch is removed, and cool to touch, carefully put it into a vice and remove the center shoulder bolt out of each clutch shoe. You wil l probably have to heat the center hub again to remove the bolts. Once you get a bolt loosened, carefully remove it with the shoe and observe the way the spring washers are stacked.

CAUTION: It is very important that the clutch stack be reassembled as it was disassembled unless new shoes are being installed then it is important to reinstall per figure 34.

Figure 34 A possible configuration of clutch spring stack. Each ‘spring’ stack contains nine springs (Belleville washers) - six arranged into four ‘fly i ng saucers’, and one turned away against the flat washer(s). Another configuration the ‘three stack’ is als o li kely. For details see Figure 34b.

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Figure 34b

Part #

Thickness mm (inch)

HCWS0801

1.4 (0.056)

HCWS0802

1.2 (0.047)

HCWS0803

0.79 (0.031)

HCWS0804

0.64 (0.025)

HCWS0805

0.51 (0.020)

HCWS0806

0.38 (0.015)

Hit

Thickness (mm)

Thickness (inch)

Softer

1.17 (0.79 + 0.38)

0.046 (0.031 + 0.015)

1.30 (0.79 + 0.51)

0.051 (0.031 + 0.020)

Stock

1.4

0.056

1.58 (1.2 + 0.38)

0.062 (0.047 + 0.015)

Harder

1.71 (1.2 + 0.51)

0.067 (0.047 + 0.020)

Clutch adjustment washers

Your Cobra comes stock with a single flat washer at the bottom of the spring washer stack. The thickness of that flat washer is 0.056” (1.4mm). Cobra offers several thicknesses of thin adjustment washers that allow clutch engagement tuning. Increasing the flat washer(s) thickness increases the engine speed for clutch engagement thus increasing the abruptness of clutch engagement (harder hit). Conversely, decreasing the flat washer(s) thickness decreases the engine speed for clutch engagement thus decreasing the abruptness of clutch engagement (softer hit).

Use the table above to order adjustment washers. Replace the stock washer with the proper combination of adjustment washers that delivers the desired clutch hit.

CAUTION: It is easy to prematurely damage the clutch and other engine components with improper clutch adjustment. If you are unsure of how to adjust the clutch, by even the slightest, contact the Cobra Technical Support Group before making adjustments.

Clutch shoe wear:

• If the clutch has been slipping and shows signs of glazing, it is b est to replace the shoes. We have found that once the shoes are glazed, even if deglazed with emery paper or a file, the performance is reduced.

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• The best way to prevent glazing is by not gearing too high, changing the oil as

REF #

PART NO.

DESCRIPTION

ECMU0017

Crank seal

ECMU0040

Clutch to hub spacer

ECMU0003

Brass bushing

ECMU0033

Clutch Hub w/ brass bushing

CAKG0002

Clutch Complete w/ Arbor

ECMU0018

Clutch nut

specified and by not blipping the throttle. Every time you blip the throttle, you are working your clutch springs.

CAUTION: The clutch produces a tremendous amount of heat and when a rider is blipping the throttle. This makes the clutch and clutch springs wear out quicker. This also makes your engine tend to run hotter which decreases engine power and degrades ignition stator efficiency. It is important t o train your rider NOT to be a throttle 'blipper'.

CAUTION: Sludge build-up between the spring washers also keeps the clutch shoe from engaging fully and this will cause the clutch to start t o slip. So you will need to clean the sludge out or just replace the spring washers and bolts with new ones. How quickly this sludge builds up depends on how often you change your oil and whether your rider is a throttle ‘blipper’.

Figure 39,

Clutch Assembly Drawing

Page 54

CLUTCH ASSEMBLY:

1. After cleaning or replacing the spring washers, reassemble the stack up of washers.

CAUTION: It is important to reassemble the washer stack to that which is recommended or to your own specialized stack.

CAUTION: It is also important that all three shoes are stacked the same. (See figure 34)

2. Clean the threads of the stack bolt and the clutch with contact cleaner removing all old thread locking material.

3. Apply high strength (red) thread lock material to the stack bolt and tighten as tight as possible without stripping the Allen head.

CAUTION: Avoid allowing excess thread lock material to contact the spring washers and the clutch or the clutch is likely to malfunction.

4. Use fine emery paper on the center hole of the clutch and on the tapered section of the crankshaft.

5. Apply a small amount of wicking / bearing retainer (green) thread lock agent to the center tapered section of the crankshaft and taper of clutch arbor.

CAUTION: Lean the bike / engine such that any excess thread lock agent goes away from the bushing in the clutch drum.

6. Put the clutch back in.

7. Apply high strength (red) thread locking agent to the threads and install the nut and torque to 40 ft-lb (54Nm) with the special socket (see figure 35).

CAUTION: Use high strength (red) thread locker on the threads of the clutch nut. If you are using an impact socket, just zap it lightly with an air wrench to tighten it because there are only about 4 threads inside the nut and they can be easily stripped. If you are tightening it by hand, you can very carefully use a 3/4" piece of wooden dowel rod inside the exhaust port to block the piston so you can tighten the nut. Do not use something harder than your aluminum piston and do not crush the top of the piston into the ring.

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INSPECTION NOTE:

• There must be in / out play in installed clutch, 1.0 mm (0.04”)

• Should be no looseness in clutch shoes.

maximum.

• Excess in/out will cause early crank seal failure.

• A blue clutch drum is worn out from excessive slippage or improper

lubrication.

8. Install the clutch cover taking care to put the two longer bolts in their proper locations and tightening in the order specified in figure 36. (5mm hex key, 5.8 ft-lb, 7.8 Nm).

CAUTION: Prior to tightening the six clutch cover bolts, press the kick lever down to ensure proper kick gear alignment.

9. Put pipe back on and add oil (235 ml (8.0 oz) Cobra 3 Shoe Clutch Milk (Part # MCMUGF01).

Ignition

Stator care

Stator failure will result from running the bike hot. Following is a list of things that will make your engine run hot.

1. The timing should not exceed the maximum specifications listed.

2. Improper carburetor jetting.

Figure 40

Page 56

3. Improper spark plug heat range. Never run a hotter plug than the specified spark plug.

4. Clutch slippage. See “CLUTCH” section for causes of slippage.

CAUTION:

• Because of the amount of heat generated by the clutch and engine during extended periods of riding, it is advisable to remove the ignition cover afterward to allow the ignition to cool off. The heat transfers thr ough the cases and can damage the stator as it cools off because of lack of airflow around the stator. Spray the stator and rotor with CRC 3-36 or WD-40 and let it drip dry or blow it off a little with an air nozzle.

• Ignition will overheat if the gap between the rotor and stator is not large enough. There should be even clearance as the rotor rot ates relative to the stator.

• Non-resistor spark plug caps should be used. Resistor caps wi ll result in a weaker spark that will reduce performance.

• Make sure ground wires are secure.

• Make sure connections are free of dirt.

CAUTION: If the engine is hot, it is EXTREMLY important to take the ignition cover off, put a fan on it to let it cool, and spray it with CRC 3-36 or WD-40. Proper stator care is important for the durability of the ignition system. (Stator- Part # ICMU0007)

The proper ignition timing for this model of is at 0.045” before Top Dead Center (that means 0.045” before the piston reaches the highest point of it’s travel in the cylinder).

CAUTION: Advancing the ignition timing will cause the engine to run hotter, in-turn c ausing power loss, shortened clutch life, and possibly lead to premature stator failure, and can also cause detonation which can lead to premature piston and ring failure.

Tools recommended for timing service:

• Compact motorcycle dial indicator

• Universal clutch puller- a universal puller that pulls the clutch, main drive gear

and rotor. (Part # MCMUTL70).

TIMING YOUR IGNITION:

1. Remove the spark plug cap, and sparkplug.

2. Insert the dial indicator into the spark plug hole.

3. Remove the four bolts from the ignition cover.

4. Remove the water pump belt from the rotor and water pump shaft.

5. Turn the crankshaft counterclockwise until it reaches top dead center.

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6. Set the dial indicator to zero

0.045”

7. Turn the crankshaft clockwise until the dial indicator reaches 0.045” (1.14mm) from top dead center.

8. Line up the lines on the stator and the rotor (figure 37). Otherwise loosen the three 5mm bolts to adjust the stator.

before

TDC

Figure 37, Lining up the line on the rotor with the line on the stator.

Figure 38, Using a dial indicator to measure piston height for setting ignition timing.

ROTOR INSTALLATION:

1. Use wicking / bearing retainer (green) thread locker on the inside of the rotor, and on tapered part of crankshaft.

CAUTION: It is recommended that you apply the proper thread locking primer to the components that are to receive thread locking material per the manufacturers instructions.

2. Eyeball the lines on the rotor and stator then press the rotor onto the crankshaft firmly (figure 37).

3. Torque the nut on the rotor to 40 ft-lb (54 Nm) with high strength (red) thread locking agent.

4. Recheck the timing following the procedure of timing your ignition.

5. Install the water pump belt back on.

6. Bolt the ignition cover back on.

7. Put the spark plug back in, and firmly stick the spark plug cap onto the spark plug.

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Cooling System

Radiator fluid removal:

1. Remove the coolant drain plug (A) on the front of the engine case (figure 39).

Figure 39

To remove radiator cap:

1. Turn the cap counter clockwise to the first stop and wait there for a few seconds.

COBRA IMPELLER SERVICE INSTRUCTIONS

1. Remove exhaust pipe and gas tank (you will be using a propane torch in step 12.

hex head

coolant drain plug.

The water pump in the engine keeps the radiator fluid in circulat ion throughout the motor. The air stream running through the radiator cools th e radiator fluid. Therefore dirty radiators additionally reduce the cooling effect. Cobra has tested numerous brand name automotive and racing coolant / antifreeze solutions and has found Liquid Performance Propylene Glycol bas ed Mini Coolant / Antifreeze to have the greatest effect on reducing cylin der head temperatures.

2. Push the cap down and turn it further in the same direction and remove the cap. NOTE: Inspect the old coolant for visual evidence of corrosion and abnormal smell. Fill the radiator up to the bottom of the radiator f iller neck with coolant. Install the cap,

turning it clockwise about ¼ turn.

Tools recommended for impeller service:

• Flat head screwdriver

• 13mm- hex wrench

• 3mm hex key

• 4mm hex key

• 5mm hex key

• Propane torch

• 3/8” diameter x 8” long steel rod

• Hammer

Remove radiator cap and drain engine coolant by removing the 13mm-

Page 59

3. If the impeller is damaged or broken completely back flush the coolant system to

ensure no solid pieces are in the system.

8. Unscrew water elbow fitting. (Figure 40)

8. Remove ignition cover using a 4mm hex key (four places)

10.

11. Remove bearing retain er s crew using a 3mm hex key. (Figure 41 – item 2)

12. Heat engine case around area of impeller lig htly with a small Burnsmatic propane engine as shown in figure 42.

CAUTION:

Remove foot brake. Drain engine transmission oil by removing drain screw using a 13mm- hex

wrench. (item 2 in the figure below). Remove kick-starter cover using a 5mm hex key. (item 3 six places) Remove clutch and basket.

Figure 40

Remove belt retainer screw using a 4mm hex key. (Figure 41 - item 1)

Remove belt retainer, water pum p belt and wat er pump fan pulley.

Figure 41

torch. Using a 3/8” diameter x 8” long steel rod, tap impeller assembly out of

Figure 42

Page 60

Too much heat can be detrimental to the engine cases.

13. The shaft assembly is serviceabl e. Use a 1/8” hex key to remove impeller retainer screw. Remove impeller, seal and both bearings. Check shaft for wear in the area of the seal. If there is any sign of wear (like a groove) replace the shaft.

14. Reinstall new bearings, seal ( open s ide t oward impeller) and impeller. Clean all

15. long and tap on end of tube per figure 44.

16. Re-assemble in same order of disassembly.

CAUTION: Clean all threads and use green (wicking / bearing retainer) t hread locker on the be lt retainer screw.

NOTE:

Apply Ultra black Hi

the threads of the water

pump 90° elbow fitting before assembly.

NOTE:

Refill the coolant system with

Propylene Glycol based Mini

Coolant / Antifreeze. CAUTION:

Do not mix Propylene Glycol based coolant / antifreeze solutions with Ethylene Glycol based coolant / antifreeze solutions.

Figure 43

threads and use green (wicking / bearing retainer) thread locker.

Using a liberal amount of grease on the outside seal, bearings and inside of

case, reinstall bearing assembly by using a 0.500” ID by 1.000” OD steel tube 2”

Figure 44

-Temp RTV silicon gasket maker to

Liquid Performance

Page 61

Fuel & Air System

REF. #

PART #

DESCRIPTION

RCCM0001

COMPLETE CARBURETOR 14MM

RCMU0305

CARB SLIDE

RCMU0601

NEEDLE

RCMU0002

ATOMIZER

RCMU0092

MAIN JET

CHOKE JET

RCMU0301

FLOAT

RCMU0102

RUBBER CABLE CAP SEAL

RCMU0003

CABLE ADJUSTOR

RCMU0006

TOP CARB SCREW

RCMU0106

CARB TOP

RCCM1301

VELOCITY STACK – 04 and later

RCCM0314

14MM CARB RESTRICTOR

Carburetor:

Tools recommended for carburetor service:

• Small flat head screwdriver

• WD-40

• 8mm socket

5 RCMU0055 PILOT JET

27 RCMU0012 DIFFUSER 28 RCMU0016 FLOAT RETAINER PIN 29 RCMU0106 FLOAT BOWL 30

RCMU0201 BOTTOM FLOAT SCREW

Figure 49

Carburetor

Page 62

Your Cobra is equipped with an adjustable carburetor. Some fine-tuning may be needed according to weather condition and altitude. Proper jetting is very important for engine performance and engine life. Serious damage to the engine can occur if not properly adjusted.

IDLE ADJUSTMENT:

On the left side of the carburetor, there are two adjustm ent screws. The larger screw with the knurled head is the idle adjustment sc rew. To raise the idle, turn the screw in clockwise (in 1/4 turn increments) and rev the engine after each adjustment. To lower the idle, turn the screw counter-clockwise.

TOP END JETTING:

Indications that the engine is running too rich (too much fuel for the air) are:

• Engine not revving out or blubbering at high RPMs.

• Engine will not ‘clean out’

• Wet or black spark plug

NOTE: Before changing jetting be sure that the air filter is properly cleaned and has the usual amount of air filter oil. An overly dirty air filter can cause the engine to run rich.

If the engine is running rich on the top end it should be leaned out. Lean ing it out can be done by:

1. Changing the main jet to a smaller number.

2. Raising the needle clip (this lowers the jet needle) one notch at a time on the slide.

Indications that the engine is running too lean are:

• Engine cutting out on top end.

• Engine overheating and ultimately seizure.

• White spark plug

CAUTION: It is much safer to operate the engine slightly rich as opposed to slightly lean. This is because an overly rich engine will just run poorly while an overly lean engine will seize, potentially causing an expensive top end rebuild and a DNF.

To richen the carburetor:

1. Change the main jet one number at a time (larger).

2. Lower the needle clip (raising the jet needle) one notch at a time until the engine starts to blubber on the top end, then move the clip back up one notc h or until you get the blubber out.

FUEL MIXTURE SCREW

The smaller brass screw that is towards the front of the engine is a fuel mixtur e screw. This screw will also richen and lean your engine more on the bottom and mid-range. In warmer conditions, turn the screw in. In colder conditions, turn the screw out. Be sure to keep the carburetor very clean and make sure you don't

Page 63

have water or dirt in the carburetor bowl. Use automotive carburetor cleaner or WD-40 to clean the carburetor inside and out.

STOCK CARBURETOR SETTINGS

The stock carburetor settings from the factory are:

• 55 pilot jet

• 92 main jet

Cleaning the carburetor:

Clean the carburetor in a well-ventilated area, and take care that there is no spark or flame anywhere near the working area; this includes any appliance with a pilot light. Because of the danger of highly flammable liquids, do not use gasoline or low flash-point solvent to clean the carburetor.

1. Make sure the fuel is shut off.

2. Remove the carburetor.

3. Drain the fuel from the carburetor.

4. Disassemble the carburetor.

5. Immerse all the metal parts in a carburetor cleaning solution.

7.6. After the parts are cleaned, dry them with compressed air.

8.7. Blow out the fuel passages with compressed air.

8. Assemble the carburetor

9. Install the carburetor onto the motorcycle.

CAUTION:

1. The motorcycle will only operate

properly if the carburetor top is installed properly with the mounting screws, cable and choke knob oriented as shown in figure 46.

Figure 50 Proper carburetor top installation and location of rectangular slide indexing pin and vent elbows.

Reeds:

• The reeds must lay flat on the reed cage.

• If the reed tips aren’t lying flat, replace them immediately.

• The reeds must have a tight seal on the reed cage.

• If the reed is damaged in any way, replace it. This means cracks, chips,

and ruptures. Anything abnormal, replace the reeds.

Formatted: Bullets and Numbering

Page 64

Take the reed cage out and hold it up to the light and lo ok in throu gh the cage. If

Figure 51

you see light between the reed pedals and the frame, then replace the r eeds. If you do not see light, then the reeds should be ok. (See figure 47)

The presence of light indicates that the reeds should be replaced, or possibly turned over.

Exhaust

The pipe is a crucial element to a motorcycle. Any kinks, dents, or damage done to the pipe will result in a major performance loss.

NOTE: Be sure to take the pipe off, and any carbon that may be bui lt up. Carbon build up is created from exhaust. Exhaust has oils in it, and the oils cling to t he walls of the inside of the pipe. Over a long period of time, the diameter of t he pipe will decrease, due to carbon build up. So it is essential to clear the residue.

CAUTION: It is important to repack the silencer. Signs of your silencer needing to be repacked are:

• The bike is louder than normal.

• A loss of power.

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Wheels & Tires

1. Remove the four bolts with the 11mm wrench

Pop the four rubber dampers out of Push the rubber dampers into the Place the sprocket (step facing

outward) with rubber dampers, onto

Insert the 11mm bolts into the holes

Rear wheel

Rear wheel dampening Tools recommended for wheel service:

• 13mm socket

• Flathead screwdriver

• 11mm wrench or socket

• 19mm wrench

The Cobra is the only 50cc to have the rear wheel damping system. This feature prevents engine impact shock caused by hard landings. This design allows the cushioned sprocket to move forward and backwards separately from the wheel. After each moto, check the 4 rubber dampers, spacers and bolts for fatigue. You should keep extra rubber dampers in your toolbox (part # PCMU0059). Different sized sprockets are also available.

Watch for bending and warping of the outside rear damper plate. If it is bent or warped, the rubber dampers in the sprockets do not last as long as when us ing a straight unit. Usually you can straighten the plate with a hammer or just flip it over.

Changing the rubber dampers:

2. Take the backing plate off

3. Observe the four rubber dampers, and pull the sprocket upward to remove it.

Figure 52

1. the sprocket.

2. sprocket.

3. the aluminum studs.

4. Place backing plate over the dampers and sprocket.

5. and tighten to 18 ft-lb (24 Nm).

Page 66

Rear wheel pullers

Figure 53

Remove axle, and

Pull the rear wheel

Disassembly:

1. back wheel assembly.

2. pullers out of the back of the swing arm.

Rear wheel alignment: Either

• Accurately measure the distance from the swingarm pivot t o the axle center on each side or

• From the rear of the bike, sight up through both sprockets to ensure that the chain is running in a straight line (no bend in between or jog at either sprocket).

Suspension

Adjustment:

1. Front forks

1.1. Fork oil

1.1.1. Oil type

1.1.1.1. Heavier weight oil – more damping – slower responding

1.1.1.2. Lighter weight oil – less damping – quicker responding

1.1.2. Oil quantity / level

1.1.2.1. Greater quantity / higher level – greater bottoming

1.1.2.2. Smaller quantity / lower level – less bottoming resistance,

1.2. Fork spring (optional spring)

1.2.1. Stiffer spring (higher spring rate) – stiffer throughout the travel.

1.2.2. Less stiff spring (lower spring rate) – less stiff throughout the travel.

1.3. Fork height

1.3.1. Rise in clamps for quicker turning.

Tuning

resistance, stiffer near the end of the travel. less stiff near the end of the travel.

Page 67

1.3.2. Lower in clamps for improved straight line stability.

Symptom

Action

Rear end feels stiff on small bumps

Softer compression damping

Rear end ‘sways’ on straights

Harder compression damping

Bike tends to jump ‘rear end high’

Harder rebound damping

Bike tends to jump ‘rear end low’

Softer rebound damping

Frequent rear end bottoming

Harder compression damping

Bottoms after end of continuous bumps

Softer rebound damping

Rear end ‘kicks’ over square edge bumps

1) Harder rebound, 2) Softer Compression

2. Rear shock

2.1. Shock spring (optional spring)

2.1.1. Stiffer spring – stiffer throughout the travel.

2.1.2. Less stiff spring – less stiff throughout the tr avel.

2.2. Compression damping (optional valve)

2.2.1. Harder (more damping, slower) – adds resistance t o t he suspension motion when the suspension is compressing.

2.2.2. Softer (less damping, quicker) – reduces resi stance to the suspension motion when the suspension is compressing.

2.3. Rebound damping (optional valve)

2.3.1. Harder (more damping, slower) – adds resistance t o t he suspension motion when the suspension is returning to full length.

2.3.2. Softer (less damping, quicker) - reduces resistance to the suspension motion when the suspension is returning to full length

Front Forks Bottoming Too Frequently Fork oil level

If the front forks bottom harshly more than a couple of times per lap and the fork springs are proper for the weight of rider (as detailed above), try raising the fork oil level in increments of 10mm. Raising the fork oil level, reduces the air volume, and increases the stiffness of the forks late in the travel, thus adding a progressive’ feel.

Front forks feel too stiff over small bumps. Fork oil weight

If the forks feel too stiff over small bumps try decreasing the weight (increasing the viscosity) of the fork oil.

Rear suspension troubleshooting. Damping

Always start with standard settings and make damping changes in no more than two click increments and only make one change at a time.

Proactive Suspension Adjustments

Page 68

Once you have the suspension adjusted for decent overall feel, you can make

Situation

Actions

Sand track

Lower the rear end (increase race sag).

Sand track

Stiffer compression and rebound damping.

Long fast track

Lower the forks in the clamps by 3 mm.

Tight slow track

Raise the forks in the clamps by 3 mm.

Mud track

Lower the bike if the rider has difficulties touching the ground.

proactive adjustments when faced with different racing conditions.

Rear shock

The rear shock on your Cobra is adjustable to your riders weight and riding style by changing the spring rate (stiffness) of the spring and / or by changing the damping valves.

Due to the complexities of the shock absorber internals, Cobra recommends that you either send the shock back to us for damping valve changes or send the shock to a competent suspension specialist such as PR2.

Cobra offers stiffer and softer shock springs depending on the weight of your rider. See the Parts Shock section or the Optional component section at the beginning of the manual for these other components.

Front Forks

Cobra offers stiffer and softer fork springs depending on the weight of your rider. See the Parts Shock section or the Optional component section at the beginning of the manual for these other components.

The front forks are designed with the damping components in separate fork legs. The compression damping duties are performed in the right fork leg and the rebound damping duties are performed in the left fork leg. This allows easy adjustment of the damping characteristics by appropriately changing the viscosity of the fork oil in the fork leg controlling the damping characteristic that needs changed.

Example: if stiffer compression damping is required, switch from 20 (standard) weight fork oil to 25 or 30 weight oil in the right leg. If softer rebound damping is desired, switch from 20 (standard) to 15 or 10 weight fork oil in the left leg.

NOTE:

Fork oil level affects bottoming harshness, and oil viscosity affects valving speed.

Page 69

Gearing

Condition

Gear Taller

Gear Lower

For a bike with a centrifugal clutch, it’s better to be geared too low than too high.

What happens with improper gearing?

• Poor performance

• Not enough top end speed

• No snap

• Over heat clutch

• Premature failure of engine seals, bearings, & electronics

• High clutch wear

Mud

Sand

Hills

Hard Pack

Throttle Blipper (novice)*

*It may be helpful to set up the clutch to hit early for smooth power delivery

Page 70

Front Sprocket

Sprocket

Gear Ratio

2.20

2.27

2.33

14 33

2.36

2.40

14 34

2.43

2.47

14 35

2.50

2.53

2.54

14 36

2.57

2.60

2.62

14 37

2.64

2.67

2.69

stock

2.71

2.73

2.77

14 39

2.79

2.80

2.85

14 40

2.86

2.92

14 41

2.93

3.00

14 42

3.00

3.08

3.15

3.23

Rear

Page 71

Carburetion

Environmental and altitude related mixture adjustments

Condition

Mixture will be

Required adjustment

Cold air

Leaner

Richer

Warm air

Richer

Leaner

Dry air

Leaner

Richer

Very humid air

Richer

Leaner

Low altitude

Standard

None

High altitude

Richer

Leaner

Low barometric pressure

Richer

Leaner

High barometric pressure

Leaner

Richer

Although your Cobra is sent from the factory with the carburetor jetted for optimal performance, you may find it necessary to adjustment your particular jetting due to current weather conditions, altitude, fuel variations, and/or engine modifications.

CAUTION: Proper jetting is very important for engine performance and engine life. Symptoms of improper jetting are listed below.

• Symptoms of incorrect oil or oil / fuel ratio

o Poor acceleration o Misfire at low engine speeds o Excessive smoke o Spark plug fouling o Excessive black oil dripping from exhaust system

• Symptoms of too rich a fuel mixture

o Poor acceleration o Engine will not ‘rev’ out, blubbers on top o Misfire at low engine speeds o Excessive smoke o Spark plug fouling o Wet, black, or overly dark spark plug (when removed for inspection)

• Symptoms of too lean a fuel mixture

o Pinging or rattling o Erratic acceleration o Same actions as running out of fuel o High engine temperature o White spark plug (when removed for inspection)

NOTE:

When inspecting the spark plug to evaluate jetting, a properly jetted machine will produce a spark plug that is dry and light tan in color.

NOTE:

Page 72

• Before making any carburetor jetting changes verify that:

o You are using the proper fuel and oil o The fuel is fresh and uncontaminated o The oil and fuel have been mixed in the proper ratio o The carburetor is clean (no plugged jets) o The air filter is properly clean and oiled o The float height is within proper specification (proper measuring technique

is described later in this section)

NOTE:

Perform all jetting changes on a motorcycle that has been warmed up to proper operating temperature.

The carburetor on your Cobra motorcycle is quite adjustable. Figure 59 shows its range of adjustment and in particular what adjustable compon ent affects what range of operation (specifically throttle position).

Figure 59

FUEL SCREW ADJUSTMENT: Adjust for maximum idle speed

The fuel adjustment screw is located on the left side of the carburetor. It is the smaller of the two adjustment screws and requires the use of a small flat blade screw driver for adjustment. After adjusting for maximum idle speed, use the idle screw to adjust the desired idle speed.

NOTE:

If the fuel screw requires more than 3 turns out, replace the pilot jet for one that is one size richer (larger number) then readjust the fuel screw.

IDLE ADJUSTMENT: Adjust for desired idle speed

The idle speed screw is located on the left side of the carburetor. It is the larger of the two screws on the side of the carburetor and is unique with its knurled head for easy fingertip adjustment. To raise the idle, turn the screw in, clockwise, (in 1/4 turn increments) and rev the engine after each adjustment. To lower the idle, turn the screw counter-clockwise.

Page 73

TOP END JETTING: Adjust for clean full throttle acceleration

Jet your top end (main jet) based on the acceleration of your Cobra M otorcycle on the longest straight at the track. Observe any of the lean or rich symptoms (spark plug appearance and bike performance) listed above and change your jetting accordingly.

PART THROTTLE Adjust for desired acceleration

Using an area of the track that allows the rider to operate and mid throttle and transition (accelerate, or ‘roll on’) from closed, or mostly closed throttle, to a larger throttle opening. Observe the rich and lean symptoms listed above. Adjust the jet needle position by moving the clip from its curr ent position (move the clip higher on the needle to make the bike run leaner, or move the clip lower on the needle to make the bike run richer) to one higher or lower.

Troubleshooting

1) Engine not behav i ng p roperly

a) Carburetor top is installed backwards (happens a lot) b) The carburetor slide indexing pin is missing c) Wrong spark plug installed (8339 Champion to be used on ’04 or later & no

mods) d) Needle clip is on top of plastic not below e) Air leak – find where with WD40 or the like f) Ground wire or ignition leads have fault

2) Engine is down on power

a) Clutch engagement is not set properly b) Jetting is incorrect c) Silencer needs repacked d) e) Exhaust pipe

i) Has excess carbon buildup

ii) Has large dent in it f) Compression is low

i) Piston

ii) Rings g) Reeds are damaged h) Ignition timing is incorrect

3) Engine is excessively loud

a) Silencer needs to be repacked

4) Engine cuts out at high RPMs

Page 74

a) Stator bad b) Carburetor diffuser plate upside down (install like a skirt) c) Plugged fuel petcock d) Silencer core tube broken

5) Engine won’t start

a) Fuel

i) None in tank

ii) Is sour or bad b) Carburetor is dirty c) Ignition

i) Spark plug fouled

ii) Wrong spark plug installed (8339 Champion to be used on ’04 or later & no

mods) iii) Spark plug cap off iv) Engine Shut-off ‘kill’ switch is shorted v) Bad electrical ground vi) Stator winding damaged

d) Exhaust is plugged

6) Overheating

a) Bad stator b) Water pump pulleys or belt broken c) Water pump impeller broken or bolt out d) Jetting too lean e) Too much throttle blipping f) Too high gearing g) Kinked radiator hose h) Rear brake dragging i) Chain too tight j) Air lea k

7) Engine won’t idle

a) Idle knob needs adjusted b) Air leak

c) Carburetor jets are dirty

Page 75

Index

Air Filter Maintenance ................... 15

Airbox

Parts .......................................... 18

Bars and Controls ......................... 19

Break-In .......................................... 8

Carburetor

Parts .......................................... 20

Service ...................................... 61

Specifications .............................. 5

Tuning ....................................... 71

Chain

Adjustment ................................ 14

Chassis

Specification ................................ 5

Clutch

Parts .......................................... 25

Service ...................................... 50

Clutch Lubricant

Replacing .................................. 12

Compression test .......................... 42

Cooling System ............................. 58

Damper ......................................... 65

Electrical

Parts .......................................... 23

Engine

Parts List ................................... 19

Specifications .............................. 5

Exhaust ......................................... 64

Parts .......................................... 28

Fork Oil

Replacement ............................. 16

Forks

Parts .......................................... 29

Frame Parts .................................. 31

Front Brake

Adjustment ................................ 14

Parts .......................................... 34

Front Forks

Front Forks: ................................... 68

Front Wheel Parts ......................... 35

Fuel System

Gearing ......................................... 69

General Tips .................................. 10

Hardware and Fasteners

Ignition

Jetting

Lubrication

Maintenance

Oil

Optional Components ...................... 7

Parts

Service ....................................... 68

Service ....................................... 61

Frame ........................................ 31

Plastic ........................................ 36

Parts .......................................... 26

Service ....................................... 55

Timing ........................................ 56

How To ...................................... 62

Stock ............................................ 5

Troubleshooting ......................... 71

Recommended ............................ 5

schedule .................................... 11

tips ............................................. 11

Recommended ............................ 5

Airbox and Filter......................... 18

Bars and Controls ...................... 19

Bottom End & Transmission ...... 24

Carburetor ................................. 20

Clutch & Kick Starter .................. 25

Coolant System ......................... 22

Electrical .................................... 23

Engine ....................................... 24

Exhaust ...................................... 28

Forks .......................................... 29

Frame ........................................ 31

Page 76

Front Brake ............................... 34

Front Wheel ............................... 35

Ignition & Water Pump .............. 26

Inlet ........................................... 18

Plastic & Seat ............................ 36

Rear Brake ................................ 37

Rear shock ................................ 68

Rear Wheel ............................... 38

Shock ........................................ 39

Swingarm .................................. 40

Top End ..................................... 27

Triple Clamps ............................ 29

Parts List

Engine ....................................... 19

Front Forks ................................ 68

Plastic & Seat Parts ...................... 36

Pullers ........................................... 66

Rear Brake

Adjustment ................................ 15

Parts .......................................... 37

Rear Wheel

Damper ..................................... 65

Parts .......................................... 38

Pullers ....................................... 66

Reeds ........................................... 63

Shock ............................................ 68

Parts .......................................... 39

Service ...................................... 73

Spark Plug

Recommended ............................ 5

Specifications .................................. 5

torque values ............................... 6

Starting ............................................ 9

Suspension ................................... 73

Swingarm Parts ............................. 40

Tips ............................................... 10

Top End

Parts .......................................... 27

Service ....................................... 41

Torque Values ................................. 6

Transmission

Specifications .............................. 5

Transmission Lubricant

Replacing ................................... 12

Troubleshooting ............................ 73

Jetting ........................................ 71

VIN reading ................................... 10

WARNING ....................................... 2

Water Pump

Parts .......................................... 26

Wheels

Service ....................................... 65

Cobra 2005 cm50 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual