very low hrs on new piston and smoke when Cold??

[sleepin400]

I have a 400ex, it has probably 25hrs on new .040 piston and .040 bore. 11:1. I replaced the valve seals then also.

it doesn't smoke when warm or even when rapped out to limiter. But within the 1st minute of start up on a pritty cold day...say 40 degrees or so it will smoke alittle, expecially when you give it gas?

anyone elses do that. I don't like it.
thanks

[quad]

Its most likely condensation.(steam).Is it white?If it goes away after a few minutes,its normal.If the smoke would be blue,then it would be burning oil.

[ny300exrider]

could be a valve seal. my seals are getting alittle worn out, itll smoke for a minute at startup and the oil will eventually burn off. but sometimes ill get some random smoke after awhile of riding. yours might just be condensation from being cold

[balls2da-wall]

I have a 440ex and it never smoked...ever!!! then I had a race one morning when it was about 45 degrees and bam!...smoked for the 1st minute till warm. This was oil burning smoke not steam...but as soon as it was up to temp. it never did it again...i think its because when its cold the aluminum piston shrinks more in the steel sleeve and needs a few minutes to seat completly...I think you should be safe:D

-also I noticed when I switch oils it played a part in this smoking...try to stick with 10W-40

[mojoe2878]

some smoke at cold start up for a minute or so, but its normal when its on a cold start, as long as it stops after a little bit and doesnt keep doin it while you are riding then its nothing to worry about.

[sleepin400]

thanks for the info. I was feeling that it'd be impossible to smoke that quick from rings or seals. I'm sure it could happen, but its probably just "one of those things" I was just seeing if anyone else had this expirence.

thanks

[khen]

Boy sleepin400, I had that exact experience after putting in my new 416 piston. It seems to be getting better. Good info guys! I'm feeling a lot better about this now.