Top end rebuild?

[T.Hopp]

I have a 400 EX that just began to smoke on a normal basis. I'm going to check the valves first and then pull the head. If the rings are shot, are larger rings available for the stock piston? I could get the larger rings and have a machine shop hone the cylinder to fit? If not, what is the most economical way to rebuild the top end? This is for my brother-in law and his wife controls the purse strings. Ouch!

your in baltimore.. theres a few of us from the area here on the board..

you can just get new rings.. and it should be fine.. new rings should cost around 30-40 bux..

OR you can just get a bore, and a bigger piston, and give it a little more unf for not a whole lot of cash..

Give andy at dirtfirst a ring, and he can set you up 410-686-9693

Good guy to deal with..

Jesse

[T.Hopp]

I was hoping it was just rings so I could replace them and a few of the other nesessary items. I am hoping its not valve seals. I will be visiting Dirt First at just 10 minutes away.

[nopulse95]

Valve seals would actually be easier to replace, and cheaper, than piston rings.......Someone can correct me, but I think if it smokes when it's first started, and then smokes less after it warms up, it's valve seals. If it smokes all the time, or when your getting on it, then it's more likely to be piston rings.