2005-2009 Honda TRX400EX/TRX400X Service Manual, Page 333Get this manual
TROUBLESHOOTING 7Cylinder Compression Inspection
Test cylinde co pression
Is the compression low?
YES Va lve clearance too sma ll Valve stuck open orn cy linde and piston ri ngs Damaged cy linder head gasket Seized va lve Improper va lve timing
- GO STEP 8
8Carburetor Inspection
Check carburetor fo clogging
Is the carburetor clogged?
YES NOCarburetor not serviced fr eq uently en ughGO TO STEP 9
9Spark Plug Inspection
Rem ove and inspect spa rk pl ug