diganosis

[sportbikeridr]

folks... in need of help... out riding my 400ex yesturday and i noticed when i stopped a puff of blue smoke came out of the exhaust when i craked the throttle .. when i started riding the smoke cleared . now i got a new engine with 30hrs on it ? would that be the case since its new or maybe when it was shipped or from when it was being assembled ? would like some peice of mind hear from all of you riders..

[Snipe]

Blue smoke is a sign of oil. Oil can mean many things, pretty well new motor not been broken in. Or a new rebuild, or could mean things such as rings are going bad allowing oil to slip past the piston into the combustion chamber burning when firing.

First start with checking the valves and making sure there set right after that check your gaskets, top end gaskets. Make sure after getting the bike warm there is no leakage could be a blown gasket letting it smoke. Oil can be lots of different things and its mostly just a trouble shoot, check this then rule it out, check that and rule it out till you find the problem. Kinda like doing a electrical situation.

[sportbikeridr]

thanks snipe.... i'll check the things u mentioned

[Snipe]

No prob, always check the easiesest solutions first as no one wants to tear there motor apart to find its something simple that would had taken 5 mins to fix.

If it has 30 hrs on it it should be broke in. But if you bought it used it could have less or more. Im leaning towards the rings but I hope im wrong. Like I said many things can cause this problem. If it was black smoke I would say its jetting.

Sometimes when it gets a cold spell here mine will smoke a bit when first start it up and it looks white. I know its got a little lean since its cold snap in the low 70s and I have it jetted for the 80's and 90 degree summer heat. So it might be something like that if its a cold spell out of no where. Only will alot of excess fuel burn be black very minimal fuel burn will look the most part as white.

[sportbikeridr]

thanks snipe

Blue smoke is oil but if it's only on start up or lasts only a few mins of driving then its oil getting past the valves. If you see blue a lot exspecially on decell then its your rings. Your supposed to use non synthetic oil on break in.