Overview
A worn clutch drum and sprocket kit leads to sloppy chain tracking and increased vibration. This replacement unit is manufactured to OEM specifications, giving you dependable engagement and smooth power transfer without the dealer markup. It is one of those maintenance items worth keeping on the shelf so you are not stuck mid-project with a failing saw.
Key specifications
- Pitch: 3/8”
- Teeth: 7T
- Material: hardened steel
- Type: aftermarket replacement
Compatibility
Built to fit Stihl MS661 MS650 064 066 MS660 MS640 Chainsaw and other models sharing the same drivetrain layout. Always confirm your specific model and year against the compatibility list, because sprocket dimensions can differ even between closely related saws.
Installation notes
Pull off the side cover and bar assembly. Use a piston stop to lock the crank, then remove the clutch mechanism. Swap the drum, sprocket, and bearing as a set for best results. Reassemble in reverse order, set chain tension so the chain lifts slightly off the bar underside, and run a short idle test to check for vibration or noise.
Common questions
Q: Will this 1122 007 1000 clutch drum fit my Stihl MS660 with a 3/8” chain, or is it only for the 064/066 models?
Yes, this drum and 7-tooth sprocket kit fits the Stihl MS660 as well as the MS650, MS661, 064, and 066, as long as your saw is set up for a 3/8” pitch chain. The main thing to confirm is that your current setup uses a 3/8” drive system, since the drum must match the chain pitch.
Q: Does this 3/8” 7T clutch drum work with an 8” bar, and what else should I check before installing it?
It will work with an 8” bar only if the bar and chain are also 3/8” pitch and matched to the saw’s drive components. Before installing, check the rim/sprocket area for wear, inspect the clutch bearing, and make sure the bar nose and chain are not damaged from running on a worn sprocket.
Q: When replacing the clutch drum on my Stihl 066, should I also replace the bearing or grease it during installation?
It’s a good idea to inspect the needle bearing anytime you replace the clutch drum, and replace it if there is scoring, discoloration, or rough movement. If the bearing is still in good condition, clean it and apply the correct grease lightly so the new drum runs smoothly without premature wear.
