TGB Blade 250 ATV Quad Service Repair Manual, Page 66Get this manual
6CYLINDER HEADNALVE Troubleshooting
Engine performance will be affected by troubles on engine top partsThe trouble usually can be determined or by performing cylinder compression test and judging the abnormal noise generated
Low compression pressure
Improper valve adjustment Burnt or bent valve Improper valve timing Valve spring damage Valve carbon deposit2Cylinder head Cylinder head gasket leaking or damage "nit or crack cylinder