A motorbike is mechanical bond of many electronic devices reserved to perform different sort of mechanical duties and the amalgamate performance of these devices results in torque. If your bike’s exhaust doesn’t smoke, then you are lucky but if it does smoke excessively, your bike is definitely at a verge of mechanical inspection. Different colors of smoke indicate different sort of situations and depending on the color, problem can be identified very fast. Little white smoke coming out of cold exhaust is possibly a stream of vapors and would last for a very short time till the pipes get warmed up, this type of smoke is of no worries.
If exhaust continues emitting smoke even after the engine is warmed up, then this is for sure a situation where engine is asking for your immediate attention. Among some notorious causes resulting in emission of thick white smoke are blown head gasket, a ruptured cylinder head or worn piston rings attached to pistons walls. Worn piston rings are the most common cause of white smoke exhaust in motorbikes which allows engine oil to penetrate in combustion chamber and thus burns with the fuel. The common observation associated with the bike emitting white smoke is the reduced quantity of engine oil because most of the oil evaporates after burning with the fuel. So, if ever you observe oil reducing phenomenon with your bike throwing white smoke, go and get replaced ring pistons with a new set and this probably would fix white smoke exhaust from your bike.
Gray or Bluish smoke is due to incorrect air/fuel mixture and most of the times, because of loose valve seals or piston rings which need to be air tight to prevent oil penetration to the combustion chamber. You can inspect the culprit causing gray smoke blown out of your by inspecting spark plug. Remove the spark plug and have an eagle eye on its wire. Deep black powdery or flaky substance on spark is the indication that air/fuel is dense enough that it’s causing gray smoke exhaust from your bike. Loose or clogged air cleaner (filter) is an other cause of gray smoke In this case, just replace the air cleaner to get rid of gray smoke exhaust.
Don’t ride a bike exhausting smoke for long as this could potentially harm your engine’s performance, which would finally result in substantial financial loss as well. Instead, please seek professional help to rectify your bike’s problem as soon as possible.