2004-2005 Honda TRX450R Factory Sevice Manual, Page 330Get this manual
TROUBLESHOOTING
7Cylinder Compression Inspection Test cyl inder compression
Is the compression low?
YESValve clearance too small Valve stuck open Worn cylinder and piston rings Damaged cylinder head gasket Seized valve
Improper valve timing
NOGO TO STEP 8
8Carburetor Inspection