Clutch STIHL MS660 MS640 MS650 064 066 for Chainsaws #11221602002

This Stihl MS660 clutch – an aftermarket centrifugal clutch part designed for compatible professional-grade chainsaws. It is used to replace a worn or damaged clutch when the cutting chain engages unevenly, the clutch slips or does not properly transfer engine power to the clutch drum.

The clutch corresponds to part number 1122 160 2002 and is used in the Stihl 1122 series chainsaws listed below. However, before ordering it is recommended to compare the construction and number of the old part.

Compatible Stihl models

Clutch fits:

Stihl MS640
Stihl MS650
Stihl MS660
Stihl 064
Stihl 066

Part number:

1122 160 2002
1122-160-2002
11221602002

Before ordering, compare the central thread, clutch diameter, construction of the clutch weights and the old part number. The same model family may have updated components, so a physical comparison provides additional confirmation.

Clutch operation

As engine RPM increases, the clutch weights, acted on by centrifugal forces, move outward and press against the clutch drum. This causes the drum to begin turning the chain sprocket. When the engine is idling, the springs return the weights to their original position, so the chain should stop.

Worn surfaces, overheating or weakened springs can cause slipping and uneven engagement. However, chain movement at idle can also be caused by excessively high idle speed. Therefore, before replacing the clutch, the entire drive system should be evaluated.

Before installation, check the clutch drum, sprocket, needle bearing, crankshaft thread, oil pump gear and chain brake. Also remove sawdust, oil and other contaminants from the clutch area.

After installation, make sure the drum rotates properly and the chain does not move while the engine is idling. You can find more parts in the Stihl chainsaw parts category.