Overview
This aftermarket clutch drum and sprocket kit serves as a direct replacement for the factory unit on your chainsaw. The clutch drum and sprocket kit houses the sprocket that drives the chain and absorbs engagement forces from the clutch, so when the sprocket teeth wear down and the drum bore enlarges from heat and friction, cutting performance and safety both suffer. Swapping in a fresh replacement restores reliable chain drive and helps protect the rest of the drivetrain.
Key specifications
- Pitch: 3/8”
- Teeth: 7T
- Material: hardened steel
- Type: aftermarket replacement
Compatibility
This kit is compatible with Stihl MS311 MS391 MS391C Chainsaw Rim Convert part and similar models from the same product family. Verify your chainsaw’s model number before purchasing to ensure the sprocket pitch and drum bore match your saw.
Installation notes
Take off the bar, chain, and clutch cover. Immobilize the crankshaft with a piston stop and remove the clutch. Replace the entire drum and sprocket assembly along with the needle bearing. Reinstall the clutch, torque it to spec, then mount the bar and chain. Break in the new sprocket gently for the first few cuts.
Common questions
Q: Will this 3/8” 7-tooth clutch drum sprocket kit fit my Stihl MS391C, and does it replace part #1140 160 2001 directly?
Yes, this kit is made to fit Stihl MS311, MS391, and MS391C chainsaws and is intended as a replacement for part #1140 160 2001. Just make sure your saw is set up for a 3/8” pitch chain, since the drum and sprocket must match your chain pitch to run correctly.
Q: Can I use this 7T 3/8” clutch drum with my current bar and chain, or do I need to change both?
You can use it with your existing setup if your chain is 3/8” pitch and your bar is matched to that same chain size. The 7-tooth sprocket needs the correct pitch chain to seat properly, so it’s a good idea to confirm your current chain specs before installation.
Q: What should I check when installing this clutch drum sprocket kit on an MS311 or MS391?
Clean the clutch area thoroughly and inspect the needle bearing, washer, and chain brake area for wear before installing the new drum. It’s also smart to lightly grease the bearing and check sprocket wear regularly, because a worn drum can shorten chain life and affect cutting performance.
