Are you experiencing chain slippage on your chainsaw during cutting?
Earlier this year I changed the sprocket in my Husqvarna 257 Chainsaw and I thought it would be helpful to share how to do this.
The sprocket is the round ~1-1/2” diameter special gear, that converts the engine’s power into chain rotation. It is the mechanism that engages the chain and rapidly rotates it around the bar in its groove.
When chainsaw chains get loose, as they often do, these sprockets can allow the chain’s inward-facing teeth to skip. And over time the sprockets can become worn from the intense friction. The wear then leads to even more chain/ sprocket slips. This began to happen so much to me that I decided it was time to change my sprocket.
I considered taking it to my local Husqvarna dealer but then I figured surely I can teach myself this repair.
So I went online (Amazon), ordered the correct sprocket for my saw (Husqvarna 257), and taught myself how to change the sprocket. It was not too bad of a repair, if I can do it likely so can you.
In the photo to this post I show the old and the new sprockets side by side. The old on the left, the new on the right. As can be seen the old is worn due to many hours of use with chain slippage. This was long overdue.
Changing the Sprocket (on most Husqvarna’s)
Step one: remove the side cover by removing the same nuts that you’d remove to change the chain.
Step two: remove chain and bar.
Steep three: loosen locking nut that holds on the sprocket. This nut’s threads turn counter clockwise. So they loosen to the right. This nut was extremely difficult to remove. I recommend you use an impact wrench. I do not have a an impact wrench but after considerable effort it loosened. For this reason you may want to take your saw to a chainsaw dealer who does these repairs, or find a friend with an impact wrench.
Since my new sprocket I’ve had almost no chain slipping.
Another cause of chain slipping is a broken or non-functioning chain tensioner. I will summarize how to change this in a letter post.