Engine Rebuild

[Got_Mort03]

I have a 2003 400ex and if i run it high rpms and let off it will put out some blue smoke....sometimes alot and sometimes a little. i was wandering if i need to get new valve seals, or piston rings...but if i go to all the trouble i was going to put in a high compression piston, or a new cam while i had it all tore apart..any help on this situation would be great.

Thanks.

[Aceman]

Valve seals tend to smoke the most when the engine is cold.
Rings will smoke the whole time. Best way to check is to compression test your engine, then squirt some oil down the spark plug hole and compression test it again. If it's significantly higher the second time you need rings.

[Got_Mort03]

well if it smokes only if i let off the gas after running high rpms so it would have to be the rings then right??

[sandspanker]

;) yes sounds like it is sucking oil past the rings when you get off the throttle. good call