XR400 white smoke on start up

The wifes XR400 has white smoke on start up. Once it warms up, the smoke goes away, the bike runs fine. Any ideas? Is it a must fix ASAP? Any tips or links as to how to fix this? The bike has been sitting for about (months (pregnant), could it be old gas?

Thanks guys!


Quite possibly oil leaking past the valve seals.

See if it happens every time.

Mine smokes a little at start up.

I'd see if it keeps happening too. Wouldnt surprise me if it went away after the bike was ridden a little bit.

If you want someone to give it a good hard ride there are spots open for the Penguins ride this weekend. :naughty:

i'd say its normal. once the the engine heats up, the piston/rings expand as well as your valve train. when its cold some oil can slip past the rings or valve guides and burn in the combustion chamber. i wouldn't get worked up over it

how old is the 400?

has the top end ever been rebuilt?

chances are it is valve guide seals.

when the bike sits for a while, oil can leak past the seals and then into the comb. chamber.

when you start the bike, poof, white smoke.

only way to fix it is remove the head, valves and replace the seals.

it is not a big deal as long as you keep oil in the bike.

The bike is an 2002 with about 2k miles on it. Easy miles, not abused miles. I did a valve adjustment about 200 miles ago. Oil is changed every 300 miles.

Wish I could make that penquins ride James, but wife just had our baby boy last friday so we are out of service for a few weeks. Just trying to get her bike up to snuff before shes ready to go again.


Ohh wow congrats on the new addition Chris. :naughty: I bet you cant wait till he's big enough to hop on a 50.

Might just be condinsation in the pipe (white smoke=water, blue=oil, black=rich)imo.

P.S. Congrats on your baby boy :naughty:

probably valve guide seals. wrong time of year to worry. play with the kid,ride hard,fix it this winter

Out here winter is the best time to ride.

Out here winter is the best time to ride.


Don't let it run while on the side stand before shutting it off. If this helps, the stem seals are leaking. The head drain is on the side (what were they thinking) and oil gets trapped up there for a long time. If you don't have any other problems, I would just ride it.

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