Jump to content

XR250- smoke after rebuild

Recommended Posts

In doing some online investigating, white smoke points to valve seals or rings. Both were replaced during rebuild, along with fresh piston, valves, all gaskets.

Bike starts up easily and idles fine. It seemed that the smoke got worse as the bike got hotter. I let it idle for about 7/8 minutes, then just took it down the road maybe 500 feet total. I basically idled down the road in 2nd gear, just to get it moving. By the time I was turning around to come back to the house it seemed there was a thick stream of white smoke coming out the exhaust.

Ambient temperatures were around 3C last night.

Share this post


Link to post
Share on other sites

I had trouble with oil leaking around the pressed in valve guides. The guides were actually pretty loose in the cylinder head and oil leaked right down into the exhaust. If you spark plug looks fine and you find oil and carbon inside the exhaust pipes I would bet those guides are getting loose when the engine warms up causing the aluminum to expand more than the guides. If you order new ones they are slightly bigger so they will be tighter than the old ones. You will also need a 5mm reemer for the guide because the valves won't fit through the new guides till after they have been reemed out.  This was on my 1996 xr250r. Not sure what year yours is. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×