How does one change the sprocket on a Stihl model 041 chainsaw?

Answer 1

1. Remove the chain and bar. 2. Remove both right and left sides of the saw. The right is the fuel tank, the left is the recoil starter. Remove the fuel line from the tank. 3. Remove the "bar" handle in front and the rear throttle/handle assembly at the rear. Removing these just provides more room and access. 4. Remove the fan from the left side. 5. Position the remaining assembly in a bench vise with the srocket side facing up. Open the vise wide enough so the jaws can clamp firmly on the heavy gage steel cup shaped cover that was revealed when the fan was removed. The faces of the aluminum casting (to which the starter assembly was fastened) should rest on the tops of the vise jaws. This will allow the steel cup shaped cover to fit down into the jaws about 1/4 inch or so, providing adequate gripping surface for the jaws. 6. You are now ready to remove the sprocket. Use a socket or box end wrench to remove the nut and the cover washer under it. This is a left hand metric thread. 7. Remove the clutch assembly by carefully, and uniformly, prying up each of the three clutch arms. Move each a little at a time. A small screw driver or small pry bar works best. The assembly will not separate as the springs hold it securely together. 8. Remove the three legged nut over which the clutch assembly had been fitted. This is a left hand thread also and is VERY tight since it tightens in the direction of driving the chain. I used a map gas torch to heat the nut and cause it to expand slightly, then used a flat nosed soft pin punch and hammer to drive the nut clockwise. Do not heat the three legged nut excessively, only about 20-30 seconds total time, and move the flame uniformly around the nut. Do not heat the nut to red hot. This nut is hardened so you will not damage it, but you don't want to lose the hardness by overheating. I had to repeat this procedure twice and to hit the punch very hard, but it came loose. Be sure the vise is tight and that you have a soft area for landing in case the entire assembly does come out of the vise. 9. Let everything cool (of course) and then the sprocket will lift straight up, revealing a roller bearing underneath. 10. When reassembling, you do not need to tighten the three legged nut very tight. It will do that as it runs. Submitted by Jerry Weber, 11-19-08