How to fix a slipped cam

No replies to this topic
  • pablo83

Posted April 26, 2009 - 02:05 PM


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:
Posted Image

But the intake cam is off:
Posted Image

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):

Posted Image

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

Posted Image

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


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.