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2006 CM-50

Owners Manual

Allegan Motorsports - 800-475-5660
June 2006

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Summary of Contents for Cobra cm-50 2006

  • Page 1: Owners Manual

    2006 CM-50 Owners Manual Allegan Motorsports - 800-475-5660 June 2006...
  • 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.
  • Page 3 “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.
  • Page 4: Table Of Contents

    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...
  • Page 5 Tuning ..........................61 Suspension........................61 Rear shock ......................63 Front Forks ......................63 Gearing ........................64 Carburetion........................66 Troubleshooting ......................68...
  • Page 6: General Information

    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 Transmission / clutch oil type Cobra Venom 3 Shoe Clutch Milk Quantity 235 ml (8.0oz)
  • Page 7: Specifications - Torque Values

    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 Specifications - Torque Values Torque Value...
  • Page 8: Optional Components

    (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. Optional Components Call your dealer, or the factory, for details •...
  • Page 9: Break-In Procedure

    Break-In Procedure Your Cobra CM50 is a close-tolerance high performance machine and 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 the full 8 hours of bike break-in has elapsed.
  • Page 10: Starting Procedure

    (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.
  • Page 11: General Tips

    General Tips Always wear a helmet and other protective riding gear. 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 riders’ foot is not resting on the foot brake while they are...
  • Page 12: Maintenance

    • Every 10 hours of operation Replace the fork oil. Have the shock oil replaced by a Certified Cobra Mechanic. 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.
  • Page 13: Replacing Transmission / Clutch Lubricant

    4. After it has drained, reinstall the bolt being sure that the copper gasket is in place. Torque to 15 Nm (11 ft-lb). 5. Reapply oil from oil fill plug 235 cc Cobra Venom 3 Shoe Clutch Milk thru the fill plug.
  • Page 14: Chain Adjustment

    Cobra’s specially developed Cobra Venom 3 Shoe Clutch Milk 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 •...
  • Page 15: Front Brake Adjustment

    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.
  • Page 16: Rear Brake Adjustment

    Rear brake adjustment Tools recommended for rear brake maintenance: • 10mm open end wrench There are 2 adjustments on the brake. Figure 5, adjust brake lever free height Figure 6, adjust brake lever ‘free play’ From the brake lever: 6. Loosen the 10mm nut on the back of the brake pedal. 7.
  • Page 17: Fork Oil Replacement

    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-resistant foam filter oil. It’s very important to oil your filter consistently each time because varied amounts of oil will change your carburetor jetting.
  • Page 18 Disassembly 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.
  • Page 19: Service

    • 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 requires many kicks ~20 before you establish the most accurate reading possible.
  • Page 20: Engine Removal

    dropped to 90% of its original value the engine will be down on power and would 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. Engine is Fresh Engine Down on Power Engine NEEDS Rebuilt...
  • Page 21: Complete Engine Disassembly Procedure

    Remove the special nut / starter gear that holds on the clutch (special tool available, contact your local dealer). With the Cobra flywheel / clutch puller, remove the clutch from the crankshaft (details in Clutch Service portion of this manual).
  • Page 22: Splitting The Cases

    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.
  • Page 23: Engine Assembly

    CAUTION: Take caution when handling the crankshaft. It is the main power 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 as well as the rest of the engine.
  • Page 24 9. Torque to 12 Nm (105 in-lb) in the pattern shown in figure 21. 10. Trim away any excess gasket material if necessary. NOTE: Check engine mount holes for excess material that may cause problems in engine installation. 11. Install the piston with new wrist pin bearing and, pin and cl i ps. 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...
  • Page 25: Clutch

    Clutch CAUTION: The clutch components (arbor, shoes, bolt, and Belleville washers) on your 2006 Cobra are similar looking but different in geometry from prior years. Do not mix old and new parts as damage will occur. Cobra clutch puller assembly:...
  • Page 26 Generally reassemble the springs as you removed them from the engine or a s you received them from Cobra. This will be either a 3, 4 ½ or, 5 stack. If you are unsure call the Cobra Technical Support Group 330 549 9600, and consult the experts.
  • Page 27 0.79mm (0.031”) 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 0.031” (0.79mm). Cobra offers several thicknesses of thin adjustment washers that allow clutch engagement tuning.
  • Page 28 The best way to prevent glazing is by not gearing too high, changing the oil as 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.
  • Page 29 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 24) 2.
  • Page 30: Ignition

    Using one hand rotate the kick lever to ½ stroke and hold while tightening the six screws completely with the other hand. 8. Fill with oil (235 ml (8.0 oz) Cobra 3 Shoe Clutch Milk. Ignition Stator care Stator failure will result from running the bike hot.
  • Page 31 CAUTION: Advancing the ignition timing will cause the engine to run hotter, in-turn causing 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: •...
  • Page 32: Cooling System

    The air stream running through the radiator cools the 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 based Mini Coolant or Antifreeze to have the greatest effect on reducing cylinder head temperatures.
  • Page 33 • 3/8” diameter x 8” long steel rod Hammer • COBRA IMPELLER SERVICE INSTRUCTIONS 1. Remove exhaust pipe and gas tank (you may be using a propane torch in step 2. Remove radiator cap and drain engine coolant by removing the 13mm- hex head coolant drain plug.
  • Page 34 Figure 30 CAUTION: Too much heat can be detrimental to the engine cases. 13.The shaft assembly is serviceable. Use a 4mm 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. Figure 31 14.Reinstall new bearings, seal (open side toward impeller) and impeller.
  • Page 35 16.Re-assemble in reverse order of disassembly. CAUTION: Clean all threads and use blue (medium strength) thread locker on the belt retainer screw. NOTE: Apply Ultra black Hi-Temp RTV silicon or Teflon pipe sealant to the tapered pipe threads of the coolant fitting before assembly. NOTE: Refill the coolant system with Liquid Performance Propylene Glycol based Mini Coolant / Antifreeze.
  • Page 36: Fuel & Air System

    Fuel & Air System Carburetor: Tools recommended for Carburetor carburetor service: Small flat head screwdriver REF. # DESCRIPTION COMPLETE CARBURETOR 14MM WD-40 CARB SLIDE 8mm socket NEEDLE ATOMIZER AU 2.62 MAIN JET PILOT JET CHOKE JET FLOAT RUBBER CABLE CAP SEAL CABLE ADJUSTOR TOP CARB SCREW CARB TOP...
  • Page 37 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.
  • Page 38 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;...
  • Page 39: Exhaust

    Take the reed cage out and hold it up to the light and look in through the cage. If you see light between the reed pedals and the frame, then replace the reeds. If you do not see light, then the reeds should be ok. (See figure 35) Figure 35 The presence of light indicates that the reeds should be replaced, or possibly turned over.
  • Page 40: Wheels & Tires

    Wheels & Tires Rear wheel pullers Disassembly: 1. Remove axle, back wheel assembly. 2. Pull the rear wheel pullers out of the back of the swing arm. Figure 36 Rear wheel alignment: Either • Accurately measure the distance from the swingarm pivot to the axle center on each side or •...
  • Page 41 1.3. Fork height 1.3.1. Rise in clamps for quicker turning. 1.3.2. Lower in clamps for improved straight line stability. 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 travel. 2.2.
  • Page 42: Rear Shock

    Lower the bike if the rider has difficulties touching the ground. 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.
  • Page 43: Gearing

    Gearing 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, &...
  • Page 44 Gear Ratio Sprocket 2.20 2.27 2.33 2.36 2.40 2.43 2.47 2.50 2.53 2.54 2.57 2.60 2.62 2.64 2.67 2.69 stock 2.71 2.73 2.77 2.79 2.80 2.85 2.86 2.92 2.93 3.00 3.00 3.08 3.15 3.23 Ratio Write © Cobra R&D 2004...
  • Page 45: Carburetion

    Carburetion 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 current weather conditions, altitude, fuel variations, and/or engine modifications. CAUTION: Proper jetting is very important for engine performance and engine life.
  • Page 46 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 component affects what range of operation (specifically throttle position).
  • Page 47: Troubleshooting

    TOP END JETTING: Adjust for clean full throttle acceleration Jet your top end (main jet) based on the acceleration of your Cobra Motorcycle 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.
  • Page 48 4) Engine cuts out at high RPMs 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 None in tank ii) Is sour or bad b) Carburetor is dirty c) Ignition Spark plug fouled...

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