1998-2004 Honda Foreman 450 factory service manual, Page 468Get this manual
TROUBLESHOOTING
POOR PERFORMANCE AT HIGH SPEED
Possible cause
1Disconnect fuel hose at carburetor
Fuel flows freely
2Remove the carburetor and check- Clogged- Clean
for clogs Not clogged
Fuel flow restricted-,
Clogged fuel line Clogged fuel fill cap breather Faulty fuel valve Clogged fuel filter
3Check valve timing-Cam shaft not installed properly
Correct
4Check ignition timing-, Faulty ignition control module
Faulty ignition pulse generator
Correct
5Check valve spring-Weak - -Faulty spring