250x is smoking after rebuild--????

[willjoe86]

Hello-
I just finished rebuilding my 250x-bored it out, new piston, rings, and I replaced the cam and rocker arms.
I just started it up today and its smoking-blue smoke-not a whole lot, and one minute its smoking more than it was, and then it stops smoking altogether...
Im trying to break it in right, keeping it under half throttle, varying speed, etc.
Could it be the valves-would it smoke if I adjusted them a little bet off? How exact do they have to be?
I was also thinking that maybe theres too much oil in there?
If anyone has any ideas or comments Id greatly appreciate-I would hate to be hurting the quad by riding it like this..
Thanks!
Will

[Silverfox@C&DRacing]

should be nothing to worry about. they are going to smoke untill they are broke in. ;)

[willjoe86]

thanks a lot silverfox
everyone agree?
Will

[ghak99]

Dude, we just built 2 pretty hot 250x motors and they only smoked for like 30 seconds, if that.

How did you put you rings in?

Did you put in new valve seals?

[willjoe86]

I put the rings in by pushing them in their grooves, and sliding the piston up into the sleeve-it wasnt easy
I didnt replace the valve seals, since the valves didnt let any wd-40 thru when i put some in the ports
thanks
Will

[MotoXC33]

I just rebuilt my 400 to a 416. It didn't smoke right away then it started. Then it did more and more, come to find out it had two huge gashes in the sleeve. I never saw gashes that deap. My mechanic said it musta been dirt through the K and N air filter. It was so bad i needed a new sleeve and I bored it to a 426.
Hope that's not the case with yours...

[ghak99]

Sorry I should have been more clear!

How did you space the ring gaps out?

I am refering to the rubber seals on the top of the head.

[TRX300X]

When you put the WD-40 in the ports all you were testing was the valve's seal around the valve seat. Which is a good thing to check but WD-40 is a little thick you want to use kerosene or diesel fuel when you do that. But if your valve seals are leaking they wont leak when there's no pressure on them. For example when your engine sucks in the air/fuel mixture it creates a vaccum now say your valve seals on your intake valves are bad not only will your piston draw in the air/fuel mixture but it will also draw oil past the valve seals through the valve guide and down into the cylinder. Your engine will then try to burn the oil but it doesnt do a very good job of if and all of a sudden you have smoke like you're describing. If it doesnt smoke that bad then I wouldnt worry about it but otherwise you'll have to pull the head and put new seals in it. Also it's a good idea do pull the valves out and have the valves and valve seats lapped when you do a rebuild.

[willjoe86]

I spaced all the gaps evenly and no i didnt replace the rubber seals
thanks
Will

[willjoe86]

I spaced all the gaps evenly and no i didnt replace the rubber seals
thanks
Will