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
Built to fit Stihl MS290 MS310 MS390 029 039 MS311 MS391 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 3/8” 7-tooth clutch drum kit fit my Stihl MS391, or is it only for the older 029/039 models?
Yes, this kit is made to replace Stihl part #1125 007 1002 and fits the MS290, MS310, MS390, 029, 039, MS311, and MS391. As long as your saw is set up for a 3/8” pitch drive system, this clutch drum sprocket bearing kit is the correct match.
Q: Does this clutch drum work with any chain, or do I need a specific pitch and bar setup on my MS290?
This drum is specifically a 3/8” pitch, 7-tooth setup, so your chain and rim/drum system need to match that pitch. The listed 8” bar length setup should also match your saw’s current bar and chain configuration, so it’s best to confirm your existing chain pitch before installing.
Q: Do I need to grease the bearing when installing this clutch drum sprocket kit on a Stihl MS310?
Yes, it’s good practice to lightly grease the clutch drum needle bearing during installation and again as part of routine maintenance. While replacing the drum, also inspect the clutch shoes, worm gear, and washer/spacer orientation so the new sprocket runs smoothly and doesn’t wear prematurely.
