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 Echo CS-370 CS-440 CS-450 CS-400F CS-370F CS-4200ES CS-420ES 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
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 3/8” 7-tooth sprocket clutch drum kit fit my Echo CS-370 and replace part number 17510514630?
Yes, this kit is made to fit the Echo CS-370 and the other listed models, including CS-440, CS-450, CS-400F, CS-370F, CS-4200ES, CS-420ES, and CS-400, as a replacement for part number 17510514630. The key thing to confirm is that your saw is set up for a 3/8” pitch system, since the drum is a 3/8” 7T version.
Q: Can I use this clutch drum kit on my Echo CS-420ES with an 8-inch bar and 3/8” chain?
Yes, if your CS-420ES is running an 8-inch bar with 3/8” pitch chain, this sprocket drum matches that pitch. Make sure the rest of your cutting setup, especially the chain pitch and drive components, matches 3/8” as well, because a mismatched chain and sprocket will cause poor fit and accelerated wear.
Q: What should I check when installing this 3/8” 7T clutch drum kit on a CS-400 or CS-450?
Before installation, inspect the clutch bearing, washer, and rim/drum contact surfaces for heat damage, grooves, or excessive wear, and replace any worn support parts if needed. After installing the new drum, verify that the chain aligns correctly on the bar, spins freely by hand with the brake off, and is properly tensioned before running the saw.
