Just bought an 84 GS a few weeks ago. A few days ago I noticed that it will emit a puff of white smoke occasionally on upshifts. Seems to only happen when shifting...modulating the throttle without changing gears doesn't yeild the same results. Any thoughts?

 

Just in case this helps anybody else. I check my OMP and found that NO oil was dripping into the carb. Added 6 ounces of kart racing oil and the smoking is gone.