BannedCR500Riders.com

Have minimal hours (2 point something, I believe), on the fresh rings and water pump rebuild of the 85, everything seemed good, passed the leakdown test and the water pump seemed great, no leaks anywhere. I had the neighbor kid bugging me to fire it up one night when I had been drinking, and I couldn't say no. Brought it up to temp but did not ride the bike. Kept blipping the throttle to clear it out, but the white smoke did not seem to go away. My first suspect was a leaking head gasket, but after letting the bike cool, the rad is still full. Am I missing something here? Running Amsoil Dominator at 40:1 and jetting is crisp, she'll even idle all day long once warmed up. Would hate to have to tear it apart and buy another $25 head gasket for nothing. Should I be worried?

sounds like steam. does the white smoke disappear after a couple yards, I mean meters or does it linger or go down the street?
does it have a compression release, there was a recent one that seams to have broken into the water jacket.

I didn't really pay attention to whether or not it lingers like you said, but good point. No compression release, if it's coolant it has to be the head gasket. Others said tranny oil being sucked in through the main seal or possibly even case gasket, but I really can't see that being the case if it passed a leakdown test. Not ruling anything out just yet.

Take it out for a ride and clean it out.
The crank could be swimming in oil, I've seen that a lot.
On a non race bike, there's usually oil in the crank.
Not a bad thing in my opinion.
Of course it could be a crank seal gone bad but riding it will at least give you a better idea.