Honda CRF450R 2007 Service Manual

TROUBLESHOOTING
22-4
7. Cylinder compression Inspection
Test the cylinder compression.
Is the compression low l
YES _ . Valve clearance too small
• Valve stu ck open
• Worn cyli nd er and piston rings
• Damaged cylinde r head gasket
• Impr oper val ve timing
• Faulty decomp re sso r system
• '05 - '07: Fa u lty decompressor cam
• After '07: Faulty decompressor shaft
NO - GO TO STEP 8.
8. Carburetor In spection
Check carburetor for clogs.
Is the carburetor for clogged ?
YES _ . Ca rbur etor n ot serviced frequ ent ly e nough
• Ca rburetor dirty
• Dirt getting past ai r cleane r
NO - GO TO S TEP 9.
9. Spark Plug Inspection
Remove and inspect spark plug.
Is the spark plug fouled or discolored ?
YES _ . Plug not serviced frequently enough
• Incorrect spark plug h ea t range
• Incorr ec t spark plug gap
NO - GO TO ST EP 10.
10 . Engine Oil Inspection
Check
oil level and condit ion.
Is the level correct lind good condition ?
NO _ . Oil level t oo high
• Oil level too low
• Contaminated oil
YES - GO TO S TEP 11.
11 . Over Heating Inspection
Check
engine over h ea ting .
Is the engine overheating?
YES - . Coolant level too low
• Excessive carbon build-up in combustion chamber
• Use of poor quality fuse
• Clutch slipping
NO - GO TO STEP 1 2.
12 . lubrication Inspection
Remove cylinder head cover and inspect lubric ation.
Is the valve train lubricated properly ?
NO _. F au lty oil pump
• F au l ty press ur e relief valve
• Clogged oil passage
• Clogged oil strainer
YES - Valve train lubrication is normal.
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Honda CRF450R 2007 Specifications

General

Engine Type	449cc liquid-cooled single-cylinder four-stroke
Bore x Stroke	96.0mm x 62.1mm
Compression Ratio	12.0:1
Transmission	5-speed
Final Drive	#520 chain; 13T/48T
Front Suspension	47mm inverted Showa cartridge fork with 16-position rebound and 16-position compression damping adjustability; 12.4 inches travel
Front Brake	Single 240mm disc with twin-piston caliper
Rear Brake	Single 240mm disc
Front Tire	80/100-21
Rear Tire	110/90-19
Wheelbase	58.3 inches
Seat Height	37.6 inches
Fuel Capacity	1.9 gallons
Induction	Keihin 40mm carburetor
Ignition	CDI
Rear Suspension	Pro-Link Showa single shock with spring preload, 17-position rebound damping adjustability, and compression damping adjustment
Trail	4.6 inches