hi mosser if there is blue smoke it sounds like you are burning some oil,i would do a compression test on each cylinder to see if there is a big difference between the two cylinders,check the valve clearance on the inlet and exhaust if you have a valve sticking or not seating properly this will cause the bike to cough and splutter,if you have low compression after you have checked the valves i would take the head off and check the bores, just a note on the blue smoke if you have been running the bike for some distance misfiring or running on one cylinder you are likley to have a lot of petrol contamination thining the oil so an oil change is advisable.hope this helps steve
