Poor Performance At Low And Idle Speed - Honda TRX400EX FOURTRAX 1999 Service Manual

From page 20-2
and inspect lubrication
Valve train lubricated properly
I
Check for engine overheating
11.
Not overheating
Accelerate or run at high speed
12.
Engine does not knock

POOR PERFORMANCE AT LOW AND IDLE SPEED

1. Check carburetor pilot screw
adjustment
I
Correct
2. Check for leaking carburetor ~-
insulator
I
No
leak
3. Perform spark test
Good spark
4. Check ignition timing
Valve train not lubricated
properly
Overheating
-
Engine knocks
-
Incorrect
Leaking
Weak or intermittent spark
Incorrect
TROUBLESHOOTING
Possible cause
Clogged oil passage
Clogged oil orifice
Excessive carbon build-up in
combustion chamber
Use of poor quality fuel
Clutch slipping
Lean fuel mixture
Worn piston and cylinder
Use of poor quality fuel
Excessive carbon build-up in
combustion chamber
Ignition timing too advanced
(Faulty ICM)
Lean fuel mixture
Possible cause
See section 5
Loose carburetor insulator bands
Damaged carburetor insulator
Faulty carburetor insulator O-ring
Faulty spark plug
Fouled spark plug
Loose or disconnected ignition sys-
tem wires
Broken or shorted spark plug wire
Faulty ignition coil
Faulty ignition pulse generator
Faulty exciter coil
Faulty engine stop switch
Faulty ignition switch
Faulty ignition control module (ICM)
ICM
Faulty
Faulty ignition pulse generatoi
20-3