2000 YZ250 topend

I'm currently in the process of bringing my YZ250 back from the dead. After piston failure I've got to know my motor pretty well (not by choice). So far I've changed the Crank & crank bearings (hotrods), all seals & gaskets.

 Anyhow,I just received my piston and cylinder back from millennium technologies and it looks great. I've went with a Wiseco piston this time around, gaped the rings at.016 as per recommendation from TT. My only concern is that when I placed the cylinder head over the piston I compressed the rings by hand and kind of felt blind in seeing if they sat on the pins. The piston moves very freely but I'm considering pulling it back off to reassure myself proper alignment. does anyone have tips or tricks for this one?

Next issue is timing- I don't have access to a dail gauge, yet, is it possible to set timing based on visual TDC before installing the head?  I'm stopping by local big box store to make a leak down tester before firing it up.

All help is greatly appreciated .

Generally, if the piston is moving freely up and down, you're fine. If the ring were over an alignment pin, it would bind up noticeably. Otherwise, get a helper to drop the cylinder on while you make sure the rings are aligned.

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