Overview
When the sprocket teeth wear down and the drum bore enlarges from heat and friction, it is time to replace the clutch drum and sprocket kit. This aftermarket kit matches original-equipment dimensions and material specs, providing a reliable fix at a lower cost than going through the dealer. Keeping this component in good shape extends the life of your chain and bar.
Key specifications
- Pitch: .325”
- Teeth: 7T
- Material: hardened steel
- Type: aftermarket replacement
Compatibility
Designed for Stihl MS271 MS291 MS261 MS261C MS291C MS260C MS270 plus additional saws with identical clutch-drum geometry. Check the full compatibility chart before ordering, as small production-year changes can affect fitment.
Installation notes
Remove the clutch cover, bar, and chain. Lock the piston with a stop tool and unthread the clutch (left-hand thread on most saws). Swap the old drum and sprocket for the new kit, making sure the needle bearing is seated properly. Reinstall the clutch, cover, bar, and chain. Adjust chain tension and let the saw idle briefly to confirm smooth sprocket rotation.
Common questions
Q: Will this .325” 7T clutch drum sprocket kit fit my Stihl MS271, and can I use it with my existing .325 chain and bar?
Yes, this kit is made to fit the Stihl MS271 and also matches the listed models such as MS291, MS261, MS270, MS280, 024, and 026 that use part number 1121 640 2004. If your saw is set up for a .325 pitch chain, you can use your existing .325 bar and chain as long as they are still in good condition.
Q: I have a Stihl MS261C—how do I know if I need this 7-tooth .325 drum instead of a different sprocket setup?
Check the pitch stamped on your guide bar or the markings on your current chain; this drum is specifically for .325 pitch setups. You should also confirm your current drum matches the 7-tooth configuration and the replacement part number 1121 640 2004 before installing it on an MS261C.
Q: When replacing the clutch drum sprocket on my MS291C or 026, should I replace anything else or do any extra maintenance at the same time?
Yes, it’s a good time to inspect the rim area, clutch bearing, washer, and oil pump drive components for wear while the drum is off. Clean out packed sawdust, lightly grease the needle bearing if your model calls for it, and avoid running a worn chain or bar on a new sprocket because that can shorten the life of the new drum.
