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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 CX50JR 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.
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.
MCCJ2015.0
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Summary of Contents for Cobra CX50 JR 2015
- Page 1 WARNING THE COBRA CX50JR IS A COMPETITION MODEL ONLY AND IS NOT MANUFACTURED FOR, NOR SHOULD IT BE USED ON PUBLIC STREETS, ROADS OR HIGHWAYS.
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Page 2: Table Of Contents
Air Filter Cleaning ..................... 14 Fork Maintenance ..................... 15 Fork Air Bleeding ....................15 Fork Oil Replacement ................... 15 Cobra Frictional Drive (V3 CFD) ................16 Parts ..........................18 Parts – Airbox and Inlet System ................18 Parts – Bars and Controls ..................19 Parts - Carburetor ..................... - Page 3 Parts – Plastic & Seat ....................38 Parts – Rear Brake ....................39 Parts – Rear Wheel ....................40 Parts – Shock ......................41 Parts – Shock - Inside ....................42 Parts – Swingarm Assembly ..................43 Service ......................... 44 Engine Service ......................
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Page 4: General Information
Transmission Speed / Clutch Single / Cobra 3 shoe Final drive ratio 14/37 T Chain Cobra Venom 3 Shoe Clutch Milk Transmission / clutch oil type Transmission / clutch oil type Quantity 235 – 350 ml (8 – 12oz) Chassis Front tire 2.50 –... -
Page 5: Optional Suspension Components
Optional Suspension Components Weight of Rider (lb) Fork Spring Shock Spring KCCJ3218 Less than 38 (light) SCMUOH04 (275 lb/in) red (18 lb/in, 3.15 N/mm) KCCJ3221 SCMUOH05 (285 lb/in) 38 – 45 (std) (21 lb/in, 3.70 N/mm) yellow KCCJ3225 SCMUOH06 (295 lb/in) 46 to 55 (stiff) (25 lb/in, 4.40 N/mm) white... -
Page 6: Break-In Procedure
Break-In Procedure Your Cobra CX50 JR is a close-tolerance high performance machine and break- in time is very important for maximum life and performance. The CX50 JR can be ridden hard after the first ½ hour break-in time. Cobra recommends Bel-Ray H1-R premix oil with high octane pump gas mixed at 40:1 (150 ml oil to 2 gallons of gas). -
Page 7: Starting Procedure
Fenders can be replaced but bruised egos and other body parts take longer. CAUTION: 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. CAUTION:... -
Page 8: Maintenance
Cobra Motorcycle Tips Recommended lubricants: a. Cobra Clutch Milk is by far the best auto clutch lubricant. It is a full synthetic lubricant that has been specifically formulated for Cobra’s auto clutch and has; • Exceptional film strength over petroleum based oils or synthetic blends. -
Page 9: Schedule
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. Use ER70S6 filler if welding on the frame. -
Page 10: Replacing Transmission / Clutch Lubricant
Figure 1 3. Allow the oil to drain completely, then reinstall the oil drain plug. 4. Remove the oil fill plug and add 8.0oz of Cobra Venom 3 Shoe Clutch Milk thru the oil fill plug. NOTE: Putting additional oil, up to 350 ml (12 oz), can help clutch life. More than 350 ml (12 oz) will degrade engine performance. -
Page 11: Proper Chain Adjustment
Proper 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. A properly adjusted chain will have 50mm (2”) free movement behind the chain block with no load on the bike. - Page 12 CAUTION: Use only DOT 4 brake fluid Setting rear brake pedal position (see figure 2b): 1. Loosen the lock nut (10mm wrench). 2. Adjust the brake lever stop (10mm wrench) so that the lever is comfortably reachable in both: a. Standing riding position, and Figure 2b b.
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Page 13: Brake Bleeding Procedure
Brake Bleeding Procedure Tools Required: • Front: T10 Torx bit/driver, Cobra bleed kit (BCKG0031) • Rear: 3mm hex key (Allen wrench, T10 Torx bit/driver, Cobra bleed kit(BCKG0031) Procedure: • Remove the brake fluid reservoir cover. • Fill the syringe half full with brake fluid. -
Page 14: Air Filter Cleaning
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. -
Page 15: Fork Maintenance
Fork Maintenance Cobra strongly recommends that a professional service technician conduct all internal maintenance other than changing springs and oil. This will help to ensure safe and consistent operation. For routine maintenance, the chart below provides suggested service intervals for common procedures:... -
Page 16: Cobra Frictional Drive (V3 Cfd)
12. Reinstall the front wheel (25 ft-lb, 34 Nm). Cobra Frictional Drive (V3 CFD) The Cobra Frictional Drive (CFD) is essentially an adjustable slip clutch that dissipates torque spikes transmitted from the rear wheel to the rest of the drive line and engine. - Page 17 The slip torque value should be above 60 ft-lb (81 Nm) measured at the sprocket. To properly measure the minimum torque at which the CFD (Cobra Frictional Drive) slips 1. Access the slip clutch by draining the oil and removing the cover exposing the CFD.
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Page 18: Parts
Parts Parts – Airbox and Inlet System Airbox and Inlet System REF # PART # DESCRIPTION ZCCS0001 GASKET – REED TO CYLINDER ECMU0246 REED CAGE ASSEMBLY WITH REEDS VFORCE RCCS0002 INLET MANIFOLD HCWF0601 6mm FLAT WASHER HCBC0603 M6X30mm SOCKET HEAD CAP SCREW MCKGHO04 HOSE CLAMP –... -
Page 19: Parts - Bars And Controls
Parts – Bars and Controls Bars and Controls REF # PART # DESCRIPTION FAMU0013 HANDLEBAR - ALUMINUM TCMU0008 GRIPS (SET OF TWO) – SCOTT WAFFLE FCMU0066 THROTTLE ASSEMBLY FCPW0004 CABLE COVER FCMU0021 THROTTLE COVER FCMU0019 THROTTLE CABLE BAKG0003 BRAKE ASSEMBLY FRONT FCMU0033 KILL SWITCH ASSEMBLY HCBC0803... -
Page 20: Parts - Carburetor
Parts - Carburetor Carburetor REF. # PART # DESCRIPTION RCCM0001 COMPLETE CARBURETOR 14MM RCMU0305 SLIDE - #40 RCMU0601 NEEDLE - W7 RCMU0024 ATOMIZER AU2.62 RCMU00xx MAIN JET, xx denotes size RCMU00xx PILOT JET, xx denotes size RCMU0301 FLOAT RCMU0102 RUBBER CABLE CAP SEAL RCMU0003 CABLE ADJUSTOR RCMU0006... -
Page 21: Parts - Coolant System
Parts – Coolant System Coolant System REF # PART # DESCRIPTION FCCJ0004 RADIATOR WITH CAP MCMUHO02 RADIATOR HOSE LEFT MCMUCL07 HOSE CLAMP EACJ0001 MOUNTING BRACKET – RADIATOR BOTTOM HCBC0608 M6X55mm SOCKET HEAD CAP SCREW HCNL0601 M6 LOCK NUT MCKGGR00 GROMMET – RADIATOR MOUNTING MCCMHO01 RADIATOR HOSE RIGHT TCCJ0001... -
Page 22: Parts - Electrical System
Parts – Electrical System Electrical System REF # PART # DESCRIPTION ICCJ0001 COIL W/SPARK PLUG CAP ECMU0010C SPARK PLUG, AUTOLITE COPPERLITE ECMU0010I SPARK PLUG, AUTOLITE IRIDIUM FCMU0033 KILL SWITCH ASSEMBLY HCBH0502 M5X16mm HEX HEAD SCREW (2 REQ’D) HCWF0501 5mm WASHER (2 REQ’D) HCWP0002 5mm WASHER SPECIAL (2 REQ’D) HCNL0501... -
Page 23: Parts - Engine - Bottom End And Transmission
Parts – Engine – Bottom End and Transmission Engine Bottom End and Transmission REF # PART # DESCRIPTION 1 & 2 EKCS0003 ENGINE CASE SET WITH BEARINGS & SEALS ZCCS0005 GASKET, CRANKCASE CENTER HCBC0605 M6X40mm SOCKET HEAD CAP SCREW (6 REQ’D) HCBC0608 M6X55mm SOCKET HEAD CAP SCREW (1 REQ’D) HCBC0606... -
Page 24: Parts - Engine Clutch And Kick Lever
Parts – Engine Clutch and Kick Lever... - Page 25 Engine – Clutch and Kick Starter REF # PART # DESCRIPTION CAMU0002 CLUTCH COMPLETE ASSY - 5GX CAMU0009 3 SHOES & WASHER STACKS W BOLTS - 5GX CCMU0005 CLUTCH ARBOR – 3 SIDED SPLINE CAMU0014 WASHER STACKS - SET OF 3 - CLUTCH - 5GX HCBT0001 BOLT - TORX - 5GX CLUTCH - M6 X 29 CCMU0008...
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Page 26: Parts - Engine - Water Pump
Parts – Engine – Water Pump Engine – Water Pump REF # PART # DESCRIPTION EKMU0011 WATER PUMP KIT WITH IMPELLER ECKG0142 SHAFT, WATER PUMP ECKG0072 BEARING, WATER PUMP ECKG0074 SEAL, WATER PUMP SHAFT ECKG0073 IMPELLER, WATER PUMP (ALUMINUM) HCBC1512 M5X12mm SOCKET HEAD CAP SCREW (STAINLESS) ECMU0167 BEARING –WATER PUMP BIG... -
Page 27: Parts - Engine - Top End
Parts – Engine – Top End Engine – Top End REF # PART # DESCRIPTION ECCJ0001 CYLINDER (INCLUDES PISTON, RINGS, PIN & CLIPS) ZCMU0011 BASE GASKET (0.25mm) THICK ZCMU0703 BASE GASKET (0.30mm) THICK ZCKG0501 BASE GASKET (0.40mm) THICK (STANDARD) ZCMU0705 BASE GASKET (0.50mm) THICK ZCMU0706 BASE GASKET (0.60mm) THICK... -
Page 28: Parts - Exhaust System
Parts – Exhaust System Exhaust System REF # PART # DESCRIPTION XCCJ2009 CX50JR EXHAUST PIPE ZCMOTE11 HEADER PIPE O-RINGS (2 REQ’D) XCMU0005 EXHAUST SPRING - SHORT MCMUGR02 GROMMET KIT XCMU0028 PIPE / SILENCER SEAL XCMU0032 SILENCER MCMUGR03 MOUNTING GROMMET (2 REQ’D) TCKG0001 SPACER (2 REQ’D) HCWF1478... -
Page 29: Parts - Forks & Triple Clamps
Parts – Forks & Triple Clamps Front Forks and Triple Clamps REF # PART # DESCRIPTION KACJ0001 FORK ASSEMBLY FORK LEGS ONLY KCMU0011 FORK GUARD SET TCC60019 WASHER FORK GUARD (4 REQ’D) HCBC0601 M6X16mm, SOCKET HEAD CAP SCREW (4 REQ’D) BCC60015 BRAKELINE CLAMP HCBC0612... -
Page 30: Parts - Forks - Leg Assembly - Brake Side
Parts – Forks – Leg Assembly – Brake Side... - Page 31 REF # PART # DESCRIPTION HCBC0408 4 X 8 SHCS CLEAR ZINC ZCKG0001 GASKET, BLEED SCREW FORK KCCS0004C FORK CAP - CONVENTIONAL 32MM USD ZCMUOR18 O-RING – 3mm x 27mm ID KCCS0036 FORK - SPRING WEAR PLATE 32MM KCCS0005 FORK - OUTER TUBE 32MM KCCS0035 RING CLIP FORK OUTER WEAR RING 32MM KCCS0006...
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Page 32: Parts - Forks - Leg Assembly - Non-Brake Side
Parts – Forks – Leg Assembly – Non-Brake Side... - Page 33 REF # PART # DESCRIPTION HCBC0408 4 X 8 SHCS CLEAR ZINC ZCKG0001 GASKET, BLEED SCREW FORK KCCS0004S FORK CAP - CONVENTIONAL 32MM USD ZCMUOR18 O-RING PV SOLENOID - CX65 KCCS0036 FORK - SPRING WEAR PLATE 32MM KCCS0005 FORK - OUTER TUBE 32MM KCCS0035 RING CLIP FORK OUTER WEAR RING 32MM KCCS0006...
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Page 34: Parts - Frame - Mounting Hardware I
Parts – Frame – Mounting Hardware I Frame – Engine, Swingarm, Tank, and Pipe Mounts REF # PART # DESCRIPTION WCMU0016 SWINGARM BOLT HCNL1201 M12 SWINGARM LOCK NUT HCBH0880 M8X80mm SOCKET HEAD CAP SCREW HCNL0801 M8 LOCKNUT MCMUGR02 GROMMET KIT PIPE & SPACER HCBF0635 M6X35mm FLANGE HEAD BOLT HCHA0003... -
Page 35: Parts - Frame - Mounting Hardware Ii
Parts – Frame – Mounting Hardware II Frame – Seat, Fender, Right Side Panel, Radiator & Shock Mounts REF # PART # DESCRIPTION FACJ2012 FRAME CX50 JR HCBF1040 M10X40mm FLANGE HEAD BOLT ECCJ0001 MOUNTING BRACKET – RADIATOR BOTTOM HCBC0608 M6X55mm SOCKET HEAD CAP SCREW HCNL0601 M6 LOCK NUT MCKGGR00... -
Page 36: Parts - Front Brakes
Parts – Front Brakes Front Brakes REF # PART # DESCRIPTION BAKG0003 FRONT BRAKE ASSEMBLY BCKG0030 HOSE – BRAKE FRONT BCKG0023 ALLOY BRAKE LEVER BCKG0024 BRAKE PERCH & MASTER CYLINDER ASSY W/ LEVER BCKG0029 CALIPER – FRONT BKKG0001 KIT BRAKE PADS, WITH “E” CLIP BCMU0503 BRAKE ROTOR HCBC0501... -
Page 37: Parts - Front Wheel
Parts – Front Wheel Front Wheel REF # PART # DESCRIPTION WACJ0001 WHEEL WITH BEARINGS SPOKE STYLE WCMU0016 FRONT AXLE HCBC0501 M5X12mm SOCKET HEAD CAP SCREW (6 REQ’D) BCMU0503 BRAKE ROTOR – FRONT WCMU0101 WHEEL SPACER LEFT (SHORT) WCMU0120 BEARING – WHEEL (2 REQ’D) WCCJ0004 SPACER –... -
Page 38: Parts - Plastic & Seat
Parts – Plastic & Seat Plastic and Seat REF # PART # DESCRIPTION TCHA0107FLL FRONT FENDER - FLO YELLOW TCHA0107x FRONT FENDER x – DENOTES COLOR BLK, WHT, YEL, FLO HCBF0616 FENDER BOLT, M6X16mm FLANGE HEAD (4 REQ’D) TCC60002W NUMBER PLATE – FRONT TCC60002x FRONT PLATE x –... -
Page 39: Parts - Rear Brake
Parts – Rear Brake Rear Brake System REF # PART # DESCRIPTION BAKG0002 BRAKE SYSTEM – REAR (M/C-LINE-CALIPER) BCMU0027 BRAKE PIVOT BOLT BCMU0501 SEAL – BRAKE PEDAL (2 REQ’D) BCMU0029 BRAKE PEDAL – ASSEMBLY 50cc – WITH TOE PIECE BCMU0023T TOE PIECE HCBC0501 M5X 12mm SOCKET HEAD CAP SCREW... -
Page 40: Parts - Rear Wheel
Parts – Rear Wheel Rear Wheel REF # PART # DESCRIPTION WAKG2007R REAR WHEEL W/BEARINGS WCMU1075D TIRE – REAR 10X2.75” DUNLOP MX52 WCMUTU10 TUBE, 10" PCMU0001 MASTER LINK 420 PCMU0086 CHAIN 420 X 86 PCMU0138 38T SPROCKET (STANDARD) PCMU01xx SPROCKET xx DENOTES TEETH – RANGE OF TEETH (34-45) HCBH0702 M7X30mm HEX HEAD BOLT (4 REQ’D) HCWF0701... -
Page 41: Parts - Shock
Parts – Shock Rear Shock REF# PART # DESCRIPTION SACJ2012 SHOCK ABSORBER SCMU0043 SHOCK – BEARING SPERICAL SHOCK MOUNT – (2REQ’D) SCMU0039 O-RING – SHOCK – BUSHING (4 REQ’D) SCMU0042 SHOCK – MOUNT BUSHING (4 REQ’D) SCMU0058 SHOCK – WHITE NYLON TIP SET SCREW M6-1.0 SCMU0056 SHOCK –... -
Page 42: Parts - Shock - Inside
Parts – Shock - Inside Rear Shock REF# PART # DESCRIPTION SCMU0037 O-RING LOW SPEED COMP ADJUSTER SCMU0038 O-RING HIGH SPEED COMP ADJUSTER SCMU0036 O-RING COMP ADJUSTER CAP SCC60007 O-RING COMPRESSION ADJUSTER SCMU0051 O-RING - IFP SCMU0052 IFP SEAL BAND SCMU0033 O-RING SHOCK BASE SCMU0050... -
Page 43: Parts - Swingarm Assembly
Parts – Swingarm Assembly Swingarm REF # PART # DESCRIPTION GACJ2011 SWINGARM GCMU0001 SWINGARM BUSHING (SINGLE PIECE) (4 REQ’D) GCCJ0001 SPACER - PIVOT TUBE (2REQ’D) GCMU0017 CHAIN GUARD HCFH0512 M5X12mm FLAT HEAD SCREW HCWF0501 5mm FLAT WASHER HCNL0501 M5 LOCK NUT HCBF0620 M6X20mm FLANGE HEAD BOLT (2 REQ’D) PAKG0001... -
Page 44: Service
CAUTION: • There is a large wide range of variability in reading compression gauges. • The head volume of this Cobra Motorcycle is very small and requires 20 kicks before you establish the most accurate reading possible. • Because of the geometry of the spark plug used in this Cobra Motorcycle, the adapter used with your compression tester must have a similar volume protruding into the combustion chamber to establish an accurate value. -
Page 45: Base Gasket Selection
• measurement calipers When rebuilding the ‘top end’ of your Cobra motorcycle, care must be taken to When rebuilding the ‘top end’ of your Cobra motorcycle, care must be taken to When rebuilding the ‘top end’ of your Cobra motorcycle, care must be taken to ensure the proper squish clearance. - Page 46 If top end parts are changed during the course of the maintenance, the squish clearance should be measured, and possibly a different base gasket will be required. The easiest way to measure squish clearance is with 1mm to 1.5mm thick flexible solder wire (available through most popular electronic stores).
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Page 47: Engine Removal
3. Using a flywheel holding tool and 14mm socket remove the nut that secures the flywheel. 4. Using the Cobra flywheel / clutch puller (#MCMUTL70), remove the flywheel from the crankshaft. 5. Remove the stator (4mm Allen). -
Page 48: Top End Disassembly Procedure
7. Remove the clutch nut / starter gear that holds on the clutch using the clutch nut removal tool (#ECMU0078). 8. With the Cobra flywheel / clutch puller (#MCMUTL70), remove the clutch from the crankshaft (details in Clutch Service portion of this manual). -
Page 49: Splitting The Cases
INSPECTION NOTE: Inspect the piston for abrasions and deposits on the top and sides and clean or replace as necessary. INSPECTION NOTE: Piston ring end gap should be between 0.006” (0.16 mm) and 0.020” (0.5 mm) Splitting the Cases 1. Remove the fasteners holding the two halves of the crankcase together. 2. - Page 50 9. Trim away any excess gasket material if necessary. NOTE: Check engine mount holes for excess material that may cause problems in engine installation. 10. Install the piston with new wrist pin bearing and, pin and clips. CAUTION: Be sure to install 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.
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Page 51: Clutch
1/8 to ¼ turn). Clutch New for 2014, Cobra has again improved the clutch design. The new washer stacks are similar but of a different more heat resistant material, the shoulder bolts have been replaced with a patent pending sleeve bolt assembly, and the shoes and basket have been modified to improve the oil flow though. - Page 52 2. Remove the clutch nut (not left hand thread) on the end of the crankshaft with the clutch nut removal tool. 3. Attach the Universal Puller. There are three 6mm clutch puller holes located on the ends of the center hub. (figures 30 & 4.
- Page 53 If you do not apply heat to the arbor near the clutch bolt threads you will very likely break the Torx bit upon attempted removal. The spring stacks in your Cobra clutch will contain 11 individual springs and flat washer(s) configured as a 5 ½ stack. See figure 32. This clutch is designed such that it reconfigured by the customer to achieve different clutch engagements ‘hits’...
- Page 54 Clutch adjustment washers Your Cobra comes stock with flat washer(s) at the bottom of the spring washer stack. 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).
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Page 55: Clutch Assembly
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 (295 ml (10.0 oz) Cobra 3 Shoe Clutch Milk (Part # MCMUGF32). -
Page 56: Ignition
Ignition Stator care Stator failure could 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. 3. Improper spark plug heat range. Never run a hotter plug than the specified spark plug. -
Page 57: Cooling System
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. 6. Set the dial indicator to zero 7. - Page 58 • single and double hook ends for removing plastic impeller Dead blow hammer • COBRA IMPELLER SERVICE INSTRUCTIONS 1. Remove radiator cap and drain engine coolant as described above. NOTE: If the impeller is damaged or broken completely back flush the coolant system to ensure no solid pieces are in the system.
- Page 59 7. Clean any debris or particles from the bore and use some light emery cloth to remove any scratches in the surface that the removal process may have created. 8. Lubricate the bore with grease. 9. Prepare for assembly by installing the water pump assembly into the assembly tool and align the tool with engine case making sure alignment pin is in proper hole.
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Page 60: Fuel & Air System
• Small flat head screwdriver • WD-40 • 8mm socket 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 61 If the engine is running rich on the top end it should be leaned out. Leaning 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.
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Page 62: Reeds
compressed air. 7. Blow out the fuel passages with compressed air. 8. Assemble the carburetor 9. Install the carburetor onto the motorcycle. CAUTION: 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 45. Reeds The reeds must lay flat on the reed cage. -
Page 63: Rear Wheel Pullers
• Ensure that the brake caliper is centered over the brake rotor. It a correction is needed, Cobra has thin brake shims to help make minor adjustments in alignment. • Always leave adequate free-play in the lever or pedal. -
Page 64: Front Forks
Front Forks Tools recommended for front fork service: • Flat head screwdriver Hammer • • Pick Seal driver MCMUTL02 • 9/16” (loose 14 mm) wrench • 25mm wrench or socket • 2.5 wt fork oil • FORK DISASSEMBLY PROCEDURES: o Using the 25mm wrench, remove the fork cap. o Drain the fork oil into a suitable container. -
Page 65: Rear Shock
See Optional Components section of this manual for details on these and other optional components for your Cobra Motorcycle. Rear Shock The rear shock is fully serviceable but it is recommended that only trained professionals should service your shock. Contact Cobra for questions and service of your CX50 SR shock. -
Page 66: Tuning
Tuning Clutch There are performance characteristics to observe and things to measure. 1) Performance characteristics to observe a) Clutch coming in too late i) Engine rev’s to a high RPM before moving the motorcycle ii) Clutch never fully engages on a reasonable straight stretch iii) Basket turns blue in short amount of time b) Clutch coming in too early i) Motorcycle moves too soon when accelerating off idle... - Page 67 1. Clutch spring stack to tall • Wrong configuration • Too thick a flat shim in the stack 2. Spring rate too high (wrong configuration with proper stack height) 3. Clutch arbor shoulder bolt is too short 4. Clutch shoe material has worn too thin 5.
- Page 68 A: If it is blue or purple, replace it. If it is silver or brown, you are fine. Cobra is now going to greater lengths to ensure that Cobra is now going to greater lengths to ensure that the clutch on your the clutch on your...
- Page 69 Gearing For a bike with a centrifugal clutch, it’s better to be geared too low than too For a bike with a centrifugal clutch, it’s better to be geared too low than too For a bike with a centrifugal clutch, it’s better to be geared too low than too high.
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Page 70: Suspension
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 resistance, stiffer near the end of the travel. -
Page 71: Front Fork Operation
Front Fork Operation The front suspension on the CX50SR works under the principals of hydraulic damping, and it features full adjustability to help tune the fork to meet each rider’s needs. The CARD fork contains MXT ‘Smart Leg’ technology that provides very progressive operation;... -
Page 72: Rear Shock Adjustments
Turning this screw clockwise increases damping and turning it counter-clockwise will decrease it. This is illustrated by the “HARD” and “SOFT” in the figure at the right. The Smart Leg cap is labeled “Speed Sensitive Bottoming Control”, and this adjuster provides a range of control over how progressive the fork feels. -
Page 73: Carburetion
12. Adjustment of compression damping 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 to current weather conditions, altitude, fuel variations, and/or engine... - Page 74 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 •...
- Page 75 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.
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Page 76: Troubleshooting
Troubleshooting 1) Engine not behaving properly 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 –... - Page 77 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...
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Page 78: Index
Fuel System Service ........60 Service ........60 Specifications ......4 Hardware and Fasteners Frame ........34 Tuning ........73 Plastic ........38 CFD Cobra Frictional Drive ... 16 Chain Ignition Adjustment......... 11 Timing ........56 Chassis Jetting Specification ........ 4 How To ........ - Page 79 Carburetor ......... 20 Shock Adjustments ......72 Clutch & Kick Starter ....24 Parts ........41, 42 Coolant System ......21 Slip Clutch ........16 Engine ........23 Spark Plug Exhaust ........28 Recommended......4 Forks ......... 29 Specifications ......... 4 Frame ........
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