Some of the Chinese 48-49cc two stroke engines use a centifugal clutch assembly with two half circular metal pads or shoes that are held in place by what appears to be two 14mm bolts.They have a central spring that allows the pads to expand at a certain RPM driving a drum and a shaft. Need to replace these pads (have found a source) but need to know how to hold the assembly still so that the two bolts can be removed. Is there a special tool that will keep the assembly from moving? Problem is that the assembly turns also turning the crank and the piston. I could remove the muffler and place a sleeve in the exhaust port over the piston which would keep the assembly from moving but was concerned that the piston might be damaged when exerting pressure on the bolts which were probably securely tightened during assembly.