1. The flatness of the joint surface of cylinder head and cylinder is not more than 0.05 mm.
2. Replace the bushings when the mating clearance of the connecting rod and the piston exceeds 0.1 mm. When the connecting rod is bent and twisted and cracked, the piston wears a new piece when it is severe or broken.
3. In and out of the exhaust valve damage, reset the spring elastic weakened or broken when the raft plate wear marks, even if the replacement of new pieces.
4. The gasket and the oil seal are replaced after the inspection.