426 lack of compression

I have been working on getting my '01 426 ready to ride for the last couple of days. Sunday I was not able to get it to start at all but everything felt normal other than that. Yesterday I opened up the carb to check that it was not gummed up. I did not change the o-rings in that it was Monday and no one was open. I then re-installed the carb and tried to start the bike. It seemed to try to start on the first kick but after that nothing. After kicking it quit a few time trying all the tricks I know it started to kick through the normal TDC compression. So where I could normally stand on the kick start in compression it would kick through. Any ideas? I replaced the head gasket early this year but I have started and rode it quite a bit between then and now. The only thing I got into was the carb and I wouldn't think that even if the o-rings are bad it would cause this. Any help would be appreciated.


I would take it to a shop and have a leak down test performed that should give you the answers you are or aren't looking for.

Could be your compression release cable is not returning fully and is causing the compression release to remain open. Check the cable is loose when closed and the compression release is closing properly.

This happened to me as well. I killed it and flooded it and then proceeded to kick and kick and kick. I noticed that after a while that at TDC i could kick it without the decomp lever. Now it is like that until it warms up, starts up first kick but compression is really low and burns a small amount of oil when rev'd, but just until its warm. Any ideas why it did this all of a sudden?

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