well my old 90 fxstc started smoking today. just a little when i let it idle for 20 minutes or so. wondered if i could go with a thicker weight oil, say a straight 40 weight, or is it time to re-ring. i checked the plugs and there perfect but theres a slight puff of white smoke. what do you think.

 

I think white smoke is gas - maybe just left the choke on too long when idling?

 

wish that was true, but white is oil, black is gas.

 

Not meaning to be smart here. But, white is moisture or water. Blue is oil and black is gas. Is it possible that it was excess condensation? I'd drive it more to see how it does, before tearing it down. Hopefully, if it is serious, you can make it to the winter break.. (my bad, guess you dont get a winter break out there..)Good luck with it..

 

why would you let it idle for 20 minutes?
oil circulation at idle is not great and you get no air flow for engine cooling.

 

A leak-down/compression test will check out the rings among other things. If you take off the carb and look in the manifold at the valve stems it will tell you if the intake seals are leaking. You can also take the exhaust off and see if the seals are leaking. First I would stick my finger in the exhaust and see if the pipe is a little wet and oily. Hope this helps.

 

"why would you let it idle for 20 minutes?
oil circulation at idle is not great and you get no air flow for engine cooling."
+1+1 Way toooo long to let it idle. White smoke in an air cooled engine does not idicate much of a problem. Blue is oil and black is too rich. White smoke in a liquid cooled engine would be another issue.

 

well im going to ride it today and see how it is. 6,000 miles ago it had 165 psi compression. ill also check it. i really dont think i wore out the rings in one day because i never noticed it doing this before yesterday. worse case, i guess, is that i might need rings. also thought about maybe going with a 85 big bore kit, found one for $400.00 new.

 

Had a guy stop in my shop some years ago After 30 or so minutes I walked out to see his bike Yes it was running the exhaust pipes were cherry red His last bike was water cooled !! Unreal

 

well i watched my oil temp and it never got above 190-200 so i dont think it got to hot. just for the hell of it i used my infrared temp gauge and checked the head temp and it was around 200 on the front and about 220 on the rear.