2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 517Get this manual
TROUBLESHOOTING
ENGINE LACKS POWER
1Drive Train Inspection Raise wheel off the ground and spin it by handDoes the wheel spin freely? YES NOGO TO STEP 2- Brake dragging Worn or damaged wheel hub or axle bearing Drive chain too tight 2Tire Pressure Inspection Check tire pressureAre the tire pressures low? YES NOFaulty tire valve Punctured tireGO TO STEP 33Clutch Inspection Accelerate rapidly from low to secondDoes the engine speed change accordingly when clutch is engaged? YES NOGO TO STEP 4- Clutch slipping Worn clutch discs Warped clutch plates Weak clutch springs Damaged clutch lifter arm
Additive in engine oil 4Engine Condition Inspection Accelerate lightlyDoes the engine speed increase? YES NOGO TO STEP 5- Starting enrichment (SE) valve stuck open ('04'05) Carburetor choke is on (After '05) Fuelair mixture too rich or lean Clogged air cleaner Restricted fuel flowClogged muffler Restricted fuel fill cap breather hose Excessive carbon build-up in combustion chamber