How to fix a slipped cam

I was riding the WR426 when it made an odd engine noise and lost power and compression. I had a look and found this:

Cam gear timing is set right:


But the intake cam is off:


Turns out a lack of oil to the cam bushings caused it to seize and spun the cam gear. I had checked the head recently so it must have taken too long to refill the head with oil. I had reassembled the head with assembly lube, but I did not pour oil directly into the head.

I'm taking this bike to Moab in less than a week so I don't have time to order parts. The head is fine, but upper cam bushings were overheated and the cam would not spin freely in it. I sanded the bushing down by hand with emery cloth until the cam spun smoothly in it. Then I welded the cam gear in place and put a new timing mark on it (two teeth clockwise of the original mark):


The gear metal is VERY hard. This is what it did to my favorite punch when I made the new mark:


The bike rips again. We'll see if it holds up or if the engine grenades in the middle of the White Rim Trail.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now