Engine Lacks Power - Honda TRX400EX FOURTRAX 1999 Service Manual

TROUBLESHOOTING

ENGINE LACKS POWER

1. Raise wheel off the ground
and spin by hand
Wheel spins freely
2. Checktire pressure
Pressure normal
3. Accelerate rapidly low to
second
I
Engine speed reduced when
clutch is released
4. Accelerate lightly
En ine speed increases
5. Check ignition timing
6. Test cylinder compression
I
Normal compression
I
7. Check carburetor for clogging
I
Not clogged
8. Remove and inspect
spark plugs
I
Not fouled or discolored
9. Check oil level and condition
Correct
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Wheels does not spin freely
Pressure low
Engine speed doesn't change
accordingly when clutch is
released
Engine speed does not increase
Incorrect
Low compression
Clogged
Fouled or discolored
Incorrect
Possible cause
Brake dragging
Worn or damaged wheel bearings
Drive chain too tight
Faulty tire valve
Punctured tire
Clutch slipping
Worn clutch discs/plates
Warped clutch discstplates
Weak clutch spring
Additive in engine oil
Choke valve closed
Clogged air cleaner
Restricted fuel flow
Clogged muffler
Restricted fuel tank breather tube
Faulty ignition control module
Faulty ignition pulse generator
Valve clearance too small
Valve stuck open
Worn cylinder and piston rings
Damaged cylinder head gasket
Seized valve
Improper valve timing
enough
Plugs not serviced frequently
enough
Incorrect spark plug used
Oil level too high
Oil level too low
Contaminated oil