Cobra DCX65 2003 Instruction Manual

2003 DCx65
Owners / Service Manual
“CHAMPIONS START HERE”

1
For parts orders contact your local dealer
To locate your closest Cobra dealer
log on to
www.cobramotorcycle.com
or call
[phone]
If you need technical assistance
contact your local dealer or call
the Cobra Technical Support Hotline at
[phone]
Cobra Motorcycle MFG., Inc.
11511 Springfield Road
North Lima, Ohio 44452 MCDC2003.1

2
DISCLAIMER OF WARRANTY
This motorcycle is sold “as is” with all faults, obvious or not. There are no warranties
expressed or implied, including any warranty of merchantability and warranty of fitness
for any particular purpose.
“WARNING”
THE COBRA DC65 IS A COMPETITION MODEL ONLY AND IS NOT
MANUFACTURED FOR, NOR SHOULD IT BE USEDON 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 aperson 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
Specifications –Suspension.......................................................................................8
Optional Components......................................................................................................9
Break-In Procedure....................................................................................................10
Starting Procedure.....................................................................................................11
General Tips................................................................................................................12
Maintenance....................................................................................................................13
Schedule & Tips .........................................................................................................13
M1: Replacing Transmission Lubricant...................................................................14
M2: Chain adjustment................................................................................................15
M3: Front brake adjustment......................................................................................16
M4: Clutch lever adjustment.....................................................................................16
M5: Rear brake adjustment ......................................................................................17
M6: Air Filter Cleaning ...............................................................................................18
M7: Fork Oil Replacement........................................................................................19
Engine Parts / Service...................................................................................................20
ES1: Top End Parts ...................................................................................................20
ES2: Bottom end & transmission.............................................................................20
ES3: Clutch and Shifter components......................................................................21
ES4: Ignition................................................................................................................24
ES5: Cooling System.................................................................................................25
ES6: Fuel & Air System.............................................................................................25

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ES7: Exhaust ..............................................................................................................26
Tuning ..............................................................................................................................27
Tuning 1: Carburetor..................................................................................................27
Jetting Decisions ....................................................................................................27
Jetting Changes......................................................................................................30
Tuning 2: Suspension................................................................................................34
1 Suspension Guidelines ......................................................................................35
2 Proper Suspension Adjustments for Your Rider............................................36
3 Symptoms of Incorrect Suspension Adjustment............................................40
4 Proactive Suspension Adjustments .................................................................41
5 How to Adjust the Suspension..........................................................................42
6 Suspension Reference.......................................................................................43
Troubleshooting..............................................................................................................44
Index.................................................................................................................................45

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General Information
Specifications -General
Items DC65
Dimensions
Wheelbase 44.75” (1136 mm)
Wheel size 14” (356 mm) front, 12” (305 mm) rear
Seat height
Engine
Type 2-stroke, single cylinder, reed valve
Cooling system Liquid-cooled
Displacement 64.8 cc (3.95 Cubic inches)
Bore and stroke 43 mm x 44.6 mm
Ignition system Electronic
Spark plug Splitfire SF406B
Gap 0.023” –0.025” (0.58–0.64 mm)
Fuel type Sunoco MO2X or 93 octane pump gasoline
OTHER RACE FUELS ARE NOT RECOMMENDED
Oil type Cobra Venom 2-cycle Race Oil
Fuel / oil mix ratios 32:1 to 40:1
Ignition timing 0.050”
Carburetion 28 mm PWK style
Main jet 128
Slow (Pilot) jet 38
Jet needle JJH 3rd position from the top
Float height 19 mm +0.5mm (0.75” +0.020”)
Transmission
Speed Six speed
Clutch Manual hydraulic
Final drive ratio 13/46 T
Transmission / clutch oil type 85W 90 Gear Lubricant
Quantity 530 ml (18 oz)

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Chassis
Front tire 60/100 x 14
Pressure 10 -15 psi.
Rear tire 80/100 x 12
Pressure 10 -15 psi.
Front fork Cobra USD 35 mm
Fork oil type SAE 5 weight
Fork oil amount
4 oz (118 ml)
Fork oil level
Specifications -Torque Values
Torque Value
ENGINE Fastener ft-lb in-lb Nm
Size &
Remarks
Cylinder head nuts 9.2 110 12 ¼” x 20
Engine oil drain 336 48 x 1.25
Engine oil fill 224 2.7 14 x 1.0
Spark Plug (SP) (SP) (SP) 14 x 1.25
Crank case half 560 6.8 6 x 1.0
Crank case cover 560 6.8 6 x 1.0
Flywheel rotor nut 40 480 54 10 x 1.25 (G)
Clutch hub 40 480 54 10 x 1.25 (G)
Units of mm unless otherwise specified
(G) denotes the use of wicking / bearing retainer (green) thread locking agent to
applied to the mating surfaces ofthe two components but not the threads.
(SP)To apply the proper torque to the spark plug when inserting, one must first
screw the spark plug in until the metal gasket ring causes resistance and then
turn another 1/8 to ¼ turn.

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Torque Value
CHASSIS Fastener ft-lb in-lb Nm
Size &
Remarks
Front axle nut 25 300 34 12 x 1.25
Front brake caliber 22 264 30 8 x 1.25
Front brake rotor 672 86 x 1.0 (B)
Triple clamp bolts 672 86 x 1.0
Fork cap 560 6.7 1.25” x 18
Steering head 30 350 40 1.0” x 12 (R)
Handle bar mounts 15 177 20 8 x 1.25
Handle bar clamps 15 177 20 8 x 1.25
Front engine mount 22 265 30 8 x 1.25
Rear brake lever pivot 10 120 13.6 8 x 1.25
Subframe fasteners 22 265 30 8 x 1.25
Upper shock mount 40 480 54 10 x 1.5
Lower shock mount 40 480 54 10 x 1.5
Swingarm pivot 21 250 28 14 x 2.0
Rear axle nut 25 300 34 12 x 1.25
Rear sprocket bolts 13 160 18 8 x 1.25 (B)
Rear brake caliper bolts 22 264 30 8 x 1.25
Rear brake rotor bolts 672 86 x 1.0 (B)
Units of mm unless otherwise specified
(R)designates that the application requires the use of high strength (red) thread
locking agent applied to the threads.
(B)designates that the application requires the use ofmedium strength (blue)
thread locking agent applied to the threads.

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Specifications –Suspension
Factory
setting Track 1
Track 2 Track 3 Track 4
Fork Oil
Viscosity
5 wt
Oil Height
(amount)
4 oz
(118 ml)
Fork Spring STD.
Shock Spring STD.
Preload height
Rebound
Damping (clicks
from full damp)
Compression
Damping (clicks
from full damp)

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Optional Components
•Carburetor jets
•Sprockets
oFront
oRear
•Suspension Springs
Weight of Rider (lb) Fork Spring Shock Spring
Less than 51 -SCDC0285 (285 lb/in)
51 -60 KCDCSP01
(blue, 14 lb/in) SCDC0300 (300 lb/in)
Greater than 60 KCDCSP02
(red, lb/in) SCDC0325 (325 lb/in)
SCDC0350 (350 lb/in)
•Suspension Valving
Damping Rate Fork Valving
Compression
(base valve)
Fork Valving
Rebound
(mid valve)
Shock Valving
(kit)
Soft (fast) KCDCBV01 KCDCMV01 SCDCOH01A
Standard KCDCBV02 KCDCMV02 SCDCOH01
Hard (slow) KCDCBV03 KCDCMV03 SCDCOH01B
•Flywheel weights
oMiddle weight #ECDC0200
oHeavy weight #ECDC0201