Drive Sprocket (Part 1)...

The drive sprocket is all-important in transferring the drive from the engine to your chain, and it's another consumable item that's under a lot of stress from various elements.

In this post we'll take a look at removing one common type of drive sprocket that you'd find in a Stihl chainsaw. Find out more after the jump...

Removing the sprocket on a machine such a Stihl ground saw, is a very simple process and certainly much easier than a Husqvarna (or a Stihl climbing saw for that matter) - as you may have already seen from the video in the last post.

The reason that it's so simple is due to the method of clutch drive chosen - in these saws the clutch is fitted in the main engine housing and is known as an inboard clutch. With this type of clutch, the drive sprocket can be removed just by taking off a circlip.

It's really that simple - but let's just go through the steps one-by-one:

1. Remove the side plate, bar and chain (make sure you wear gloves when handling the chain).


2. Make sure the chain brake is off (handle pulled back). If the chain brake is left on, you will not be able to remove the sprocket as the brake operates directly on the drive sprocket.


3. Remove the circlip holding the drive sprocket in place.


4. Withdraw the sprocket, it should come out easily, but if you haven't cleaned your saw for a considerable period then it may be nigh on impossible more difficult.


5. You should be able to see a [needle-roller] bearing. This will either be left on the end of the crankshaft or will have come off with the sprocket... either way, don't loose it!

The image below shows this in pictorial form, click on it to get the larger image (it's around 1Mb).

With the drive sprocket removed, you can now assess the wear on it - if you've been using it for a while then you'll probably notice scoring and general wear and tear pretty easily.

In our next post, we'll take a look at how to remove the drive sprocket from a chainsaw such as a Husqvarna, as they use a different method. After that, we'll take a closer look at that wear and how to decide when you need a new sprocket.