Just a quick question, just had the motor rebuilt raced it llast weekend. We started it last night after installing an hour meter and I noticed it was blowing some blue smoke, but the engne wasn't really warmed up yet. My question is is it fairly normal for a thumper to blow some smoke untill it warms up, were use to 2-Strokes which this is no big deal but I thought I would get some feed back since the four stoke doesn't seem to have any of the attributes as a 2-smoke. Any real thoughts would help to ease my mind??

My bike does the same thing. The piston only has one ring (1 comp +1 oil scraper) on it and does not get a full seal until it reaches it's operating temperature. I'm not talking about a smokescreen but a small amount of black smoke when you increase the revs. Once the temp comes up, the choke is off the smoke should go away.

Rings probably haven't sat fully yet against the cylinder wall. A little oil is normal, are you sure the smoke isn't indeed a light black? Black smoke is the result of too much fuel and will occur from the choke being on when the bike is cold. Both are perfectly normal symptoms and you should'nt worry about them if they go away after warming the bike up for a few minutes.

I couldn't really tell what color the smoke was it was at night in the glow of the garage lights, but I kinda figured it was normal do to the ring not seating untill it warms up. Thanks for the peace of mind

did you break the bike in hard sometimes that will cause some blowby nd u will burn a lil oil, also during the first few oil changes did you use synthetic oil, synthetic oil is more slippery and causes the rings/seals to seat improperly which also causes blow by but after break in u can use synthetic, if it is jus a lil blow by u will be all right as the other ppl said most bikes stop smoking after they are warm but im not too sure cause my yz doesnt smoke my ttr does and it stops after its warm but it seems to be getting worse every ride.. time to put it to sleep lol

It was broke in hard with Non-Synth, it stops smoking when the choke is pushed in after it warms up. Hey 05WHY how are you liking the new YZF were thinking of making the switch from yellow to blue to gain some kinda of reliability....

Is it smoking when you rev the bike, or just smoking while it's idling? If it smokes only when you rev the bike and the choke is on, then this is perfectly normal and is only due to the fact that there is extra gas in the cylinder because of the choke.