Motorcycle Repair: smoke, blown head gasket, losing coolant

Question
I have a 1989 VTR 250 interceptor and it usually runs fine, but on the highway sometimes it will start to smoke really bad. If I continue without changing speed or throttle it will just stop smoking. The bike never smokes for any extended time usually just for a few seconds. when riding in town the bike almost never smokes. What do you think could be wrong?

Answer
Justin, a few more clues would have been helpful....  how many miles on the engine, what color the smoke is, does the performance change when it is smoking and what fluids seem to be used more than usual....???

Smoke colors and causes, from the tail pipes:

White smoke = coolant = probable blown head gasket or crack in the cylinder head, weeping coolant into the intake port(s).

Blue smoke = oil = Valve stem seals worn, rings worn, crankcase breather system is full of oil solids and needs drained. Overfilling the crankcase can cause problems, as well.

Black smoke = fuel = carburation metering problems, including leaking float valve, worn jets/needles, blocked metering airways, leaking O-rings inside the carburetor, blocked/restricted float bowl venting system passages.

So, if you are losing coolant.. which you never should be
OR losing oil faster than normal
OR using more gas than normal, then those are the directions  to look towards in solving your mystery problem

Other smoke source could be something dripping down on the exhaust system and flaring off from the heat.

Bill Silver