Cobra 2006 P3-50 Owner's Manual
Owners
2006 P3-50
Parts
Service
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) 549-9600
Cobra Motorcycle MFG., Inc.
11511 Springfield Road
North Lima, Ohio 44452
MCPW2006.2
1
DISCLAIMER OF WARRANTY
This motorcycle is sold “as is” with all faults, obvious or not. There are no warranties
expressed or implied, including any warranty of merchantability and warranty of fitness
for any particular purpose.
“WARNING”
THE COBRA P3 IS A COMPETITION MODEL ONLY AND IS NOT MANUFACTURED
FOR, NOR SHOULD IT BE USED ON PUBLIC STREETS, ROADS OR HIGHWAYS.
THE USE OF THIS BIKE SHOULD BE LIMITED TO PARTICIPATION IN
SANCTIONED COMPETITION EVENTS UPON A CLOSED COURSE BY A
SUFFICIENTLY SKILLED RIDER AND SHOULD NOT BE USED FOR GENERAL
OFF-ROAD RECREATIONAL RIDING.
IMPROPER USE OF THIS MOTORCYCLE CAN CAUSE INJURY OR DEATH.
THIS BIKE IS INTENDED FOR EXPERIENCED RACERS ONLY AND NOT FOR
BEGINNERS.
IT IS YOUR RESPONSIBILITY AS THE OWNER OF THIS COBRA MOTORCYCLE
OR AS THE PARENT, OR LEGAL GUARDIAN OF THE OPERATOR, TO KEEP THIS
COBRA MOTORCYCLE IN PROPER OPERATING CONDITION.
THIS BIKE WAS DESIGNED FOR RIDERS THAT WEIGH LESS THAN 80 LBS WITH
FULL RIDING GEAR AND SHOULD NOT BE OPERATED BY RIDERS THAT WEIGH
MORE THAT.
BE SURE THAT THE RIDER ALWAYS WEARS ADEQUATE SAFETY GEAR
EVERYTIME HE OR SHE RIDES THEIR COBRA MOTORCYCLE.
IMPORTANT SAFETY NOTICE
Failure to follow WARNING instructions could result in severe injury or death to
the machine operator, a bystander, or a person inspecting or repairing the
machine.
CAUTION:
A CAUTION indicates special precautions that must be taken to avoid damage to
the machine.
NOTE:
A NOTE provides key information to make procedures easier or clearer.
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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 ..................................................................................................................9
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
Exhaust Power Regulator.........................................................................................17
Parts.................................................................................................................................18
Parts – Airbox and Inlet System I............................................................................18
Parts - Bars and Controls..........................................................................................20
Parts – Carburetor......................................................................................................21
Parts – Coolant System.............................................................................................22
Parts – Electrical System..........................................................................................23
Parts – Engine – Bottom End & Transmission......................................................24
Parts – Exhaust System............................................................................................29
Parts – Forks and Triple Clamps.............................................................................30
Parts – Frame – Mounting Hardware I....................................................................32
Parts – Front Brakes..................................................................................................35
Parts – Front Wheel...................................................................................................36
Parts – Oil Reservoir..................................................................................................37
Parts – Plastic Bodywork & Seat.............................................................................38
Parts – Rear Brake.....................................................................................................39
Parts – Rear Wheel....................................................................................................40
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Parts – Shock..............................................................................................................41
Parts – Swingarm Assembly.....................................................................................42
Service.............................................................................................................................43
Engine ..........................................................................................................................43
Clutch...........................................................................................................................43
Reeds...........................................................................................................................44
Carburetor...................................................................................................................46
Exhaust........................................................................................................................49
Rear wheel pullers .....................................................................................................49
Tuning ..............................................................................................................................50
Suspension..................................................................................................................50
Gearing ........................................................................................................................53
Carburetion..................................................................................................................54
Troubleshooting..............................................................................................................57
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General Information
Specifications - General
Items P3
Dimensions
Wheelbase 35.75” (908mm)
Wheel size 10” (254mm)
Seat height 22” (559 mm)
Engine
Type 2-stroke, single cylinder, reed valve
Cooling system Liquid-cooled
Displacement 49.8 cc
Bore and stroke 39 mm x 41.7 mm
Ignition system Digital Electronic
Spark plug Champion 8339-1, 8332-1 hotter, 8904-1 colder
Gap 0.023” – 0.025” (0.58 – 0.64 mm)
Fuel type high octane pump gasoline
Injector oil type Cobra Venom 2-cycle Race Oil
Fuel / oil mix ratios Fill oil reservoir as required
Ignition timing Fixed
Carburetion 12 mm Dell’Orto PHVA – PS
Main jet 82
RACE FUELS ARE NOT RECOMMENDED
Slow (Pilot) jet 42
Float height Non adjustable
Coolant Liquid Performance Mini Coolant / Antifreeze
Transmission
Speed Single
Clutch 3 shoe centrif ugal
Final drive ratio 10/44 T
Transmission / clutch oil type Cobra Venom 3 Shoe Clutch Milk
5
Quantity 250 ml (8.5oz)
Chassis
Front tire 2.50 – 10
Pressure 20 psi minimum
Rear tire 2.50 – 10
Pressure 20 psi minimum
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
Fork oil height 70 mm (2.75”) collapsed from top with spring (no
spacer)
Specifications - Torque Values
Torque Value Fastener
Size &
ft-lb in-lb Nm
Cylinder head nuts 8.8 105 12 M6 X 1.0
Front engine mount bolts 22 264 30 M8 x 1.25
Rear engine mount bolts 22 264 30 M8 x 1.25
Swingarm pivot bolt 21 250 28 M14 x 2
Rear sprocket bolts 18 216 24 M7 x 1
Rear axle bolts 25 300 34 M12 x 1.25
Rear shock mounts 40 480 54 M10 x 1.5
Clutch adjust access plug 10 120 14 M12 x 1.25
Clutch nut 30 360 42
Units of mm unless otherwise specified
Remarks
6
Optional Components
Call your dealer, or the factory, for details
• Carburetor jets
o Main jets #’s 74, 76, 78, 80, 84, 86, 88, 90, 92, 94
o Slow jets #’s 38, 40, 42, 45,
• Exhaust Power Regulator, ECPW0001
• Pre-filter for Airbox
• Sprockets
o Front sprocket, 11T
o Rear sprocket, 39 T – 45 T
• Suspension Springs
Weight of Rider (lb) Fork Spring Shock Spring
Less than 38 (light) KCMZ0012A
(12 lb/in, 2.10 N/mm)
38 – 45 (std) KCMZ0012
(14 lb/in, 2.45 N/mm)
46 to 55 (stiff) KCMZ0012B
(16 lb/in, 2.80 N/mm)
• Suspension Valving
Damping Rate Fork Valving
Compression
(right)
Soft (fast) KCMZ0033A KCMZ0032A SCMU0318A
Standard KCMZ0033 KCMZ0032 SCMU0318
Hard (slow) KCMZ0033B KCMZ0032B SCMU0318B
• Tires
• Tubes or ‘Tire Balls’
Fork Valving
Rebound
(left)
SCMUOH04
(red) 275 lb/in
SCMUOH05
(yellow) 285 lb/in
SCMUOH06
(white) 295 lb/in
Shock Valving
(kit)
7
Break-In Procedure
Your Cobra P3 is a close-tolerance high performance machine and break-in time
is very important for maximum life and performance. The P3 can be ridden hard
after the first ½ hour break-in time but it is recommended that no adjustments are
made to the carburetion or suspension until the full 8 hours of bike break-in has
elapsed. Also, after the engine, transmission, and drive train have been broken-in
for the full 8 hours, the bike will be faster!
Fill the fuel tank with high octane pump gas without oil. Also, fill the oil injection
reservoir with Cobra’s specially formulated Cobra Venom 2-cycle Race Oil. (Part
# MCMUOL02)
CAUTION:
Failure to use proper fuel or oil may result in premature engine wear, or damage
to the machine.
Adhering to the following break-in schedule will result in long lasting high
performance machine.
• Start bike on stand
• First 5 minute period, operate the bike on the stand with a combination of idle
and high RPM operation. (avoid prolon ged 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!
8
Starting Procedure
Before starting the machine inspect the following:
• Make sure vehicle is properly maintained (see Schedule & Tips in the
Maintenance section)
• Fill the 2-stroke injector oil reservoir with Cobra’s specially formulated Cobra
Venom 2-cycle Race Oil.
• Insure that the fuel tank contains an adequate volume of fuel to complete
the distance required. (high octane pump gas).
• Check the throttle for smooth operation and sound closing.
• 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. On the carburetor, flip the black choke knob upward from the right side of
the bike.
3. Kick start the engine by kicking the lever forward.
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.
General Tips
1. Always wear a helmet and other protective riding gear.
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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. It is acceptable and common to run 40:1, or leaner, premix in the fuel tank.
8. New chains will stretch on first use. Never install a new chain prior to a
race. Always ‘break’ them in during practice.
9. I f your young rider is initially uncomfortable with the abrupt power delivery
of the P3, install the Exhaust Power Regulator to make the bike more
easy to control while your rider gains confidence with his or her abilities and
the feel of the new machine.
10. 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, Oixxxx6xxx is a 2006 Model Year Oil Injected P3.
10
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 Fill the 2-stroke injector oil reservoir.
o Check the air filter (clean and re-oil as necessary).
o Insure the smooth operation of the throttle cable (throttle soundly
‘clacks’ shut).
o Check for frayed strands of the throttle cable inside the throttle housing
and replace if necessary.
o Check for adequate tire pressures and adjust if necessary.
o Check all nuts and bolts for proper torque and re-torque if necessary.
o Spray all moving parts with WD40 or other light oil.
o Check drive chain for
§ Proper tension and adjust if necessary.
§ Adequate lubrication and lubricate if necessary.
o Insure that the ignition stator and rotor are clean and dry.
o Check the frame for cracks in the metal or cracks in the paint that
might indicate that the metal has been stressed beyond it’s safe limits.
Replace or get properly rewelded as necessary.
o Fill the 2-stroke injector oil reservoir with Cobra’s specially formulated
Cobra Venom 2-cycle Race Oil.
• Every 2 hours of operation
o Replace the transmission oil.
• Every 10 hours of operation
o Replace the fork oil.
o Have the shock oil replaced by a Certified Cobra Mechanic.
CAUTION:
1. If y ou 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.
11
Be sure the fuel tank and carburetor have been removed and safely located
away from the welding process.
2. The frame is 4130 Chrome Moly and it is important to weld it with the proper
rod and heat settings set as light as possible. Cobra recommends replacing
the frame with a new one if the old one becomes damaged.
Replacing Transmission / Clutch Lubricant
Tools needed:
• 250 ml (8.5oz) Cobra Venom 3 Shoe Clutch Milk (Part # MCMUGF01)
• #3 Phillips screwdriver
• large flat blade screwdriver or coin
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 Phillips screwdriver, remove the oil drain bolt located on the right side
of the engine (figure 1).
Figure 1
12
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 drain screw with gasket.
5. Refill oil from oil fill plug 250 ml (8.5oz) Cobra Venom 3 Shoe Clutch Milk
(Part # MCMUGF01) thru the fill plug.
NOTE: Leaning the bike over onto it’s left hand side will facilitate the oil filling
procedure.
6. Reapply the oil fill screw, securely, being sure the gasket is in place.
CAUTION:
Cobra has spent considerable time and money developing the proper lubrication
to handle the harsh environment of the automatic clutch and transmission of this
motorcycle. Cobra was forced to put forth this effort because the other available
options and not adequate. Cobra’s specially developed Cobra Venom 3 Shoe
Clutch Milk (Part # MCMUGF01) is the recommended lubricant for your P3
motorcycle.
Chain adjustment
Tools required for chain adjustment
• 19 mm wrench or socket
• 13 mm wren ch or socket
1. Make sure that the rear
wheel is aligned
properly.
2. For proper adjustment,
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.
13
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.
NOTE:
Lubricate the chain with a light weight oil like Liquid Performance Chain Lube, or
WD40 to reduce frictional drag.
Front brake adjustment
Tools recommended for front brake maintenance:
• 10mm open end wrench
Figure 4, from the brak e lever Figure 5, from the brake hub
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.
14
CAUTION:
If you tighten the front brake up too much, the brakes may hang up causing the
brake pads to wear incorrectly and prematurely.
Rear brake adjustment
Tools recommended for rear brake maintenance:
• 10mm open end wrench
There are 2 adjustments on the brake.
Figure 6, adjust brake lever free height Figure 7, adjust lever ‘free play’
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 remain engaged. If so, the
brake pads will burn up, and need 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.
15
4. Clean the filter in a nonflammable solvent to remov e the filter oil.
Do not clean the air filter with gasoline or other highly volatile petroleum product.
Diesel fuel or kerosene would be preferred but caution should still be taken. Hot
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-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.
8. Reinstall the filter / boot assembly by pushing it down and forward into the
airbox making sure the letters “PW” 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
16
• 19 mm wrench or socket (two required)
• Spring clip remover
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.
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.
Exhaust Power Regulator
As an entry level race machine, the Cobra P3
comes with an optional Exhaust Power Regulator
(EPR) (figure 9b) that when installed, between the
exhaust pipe and cylinder flange, will cut the peak
rear wheel power by ½. As your rider’s skills
progress, the EPR can be opened up to the etched
line (18mm diameter drill) to deliver ¾ power or
removed it completely for full race power.
Figure 9b
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