Engine Lacks Power - Honda CRF450X 2005 Service Manual

ENGINE LACKS POWER
1. Drive Train In spection
Raise wheel off the ground and spin by hand.
Did the wheel spin freel y?
NO _ . Brake dragging
• Worn or damaged wheel bearings
• Bent axle
• Drive chain too tight
YES - GO TO STEP 2.
2. Tire Pressure Inspection
Check tire pressure.
Is the tire pressures low?
YES _ . Faulty tire valve
• Punctured tire
NO - GO TO STEP 3.
3. Clutch Inspection
Accelerate rapidly from low to second.
Did the engine speed change accordingly when clutch
is
engaged?
NO _ . Clutch slipping
• Worn clutch discs/plates
• Warped clutch discs/plates
• Weak clutch spring
• Sticking clutch lifter
• Additive in transmission oil
YES - GO TO STE P 4.
4. Engine Condition Inspection
Accelerate lightly.
Did the engine speed increase?
NO _ . FueVair mixture too rich or lean
• Clogged air cleaner
• Restricted fuel flow
• Clogged muffler
• Clogged fuel tank breather hose
• Carburetor choke is on
• Excessive carbon bui ld-up in combustion chamber
YES - GO TO STEP 5.
5.
Engine
Knocking Inspection
Accelerate or run at high speed.
Is there knocking?
YES _ . Worn piston and cylinder
• Use of poor quality fuel
• Excessive carbon build-up in combustion chamber
• Ignition timing too advance (Fau lty leM )
• Lean fuel mixture
NO - GO TO STEP 6.
6. Ignition Timing Ins pection
Check ignition timing .
Is the ignition timing correct?
NO _ . Faulty ignition cont rol module OCM)
• Faulty ignition pulse generator
YES - GO TO STEP 7.
TROUBLESHOOTING
22-3