1995 KTM 250-EXC Buring Oil

You possibly have a bad seal on your crank. Its called a labyrinth seal and it will be on your clutch side because it is drawing in crankcase oil. the other side would make it run lean by drawing in air by the stator. if it is eating crankcase oil and not leaking it, it is most likely your problem. you can do a leakdown test on it to confirm the problem. put the piston at bottom dead center and compress the cylinder to about 10 pounds of air using a leakdown tester or a compression tester hose that can be used to hook up to an air compressor somehow and hold the pressure, but do not go above that because you could damage those seals with too much pressure. Check to see if the cylinder will hold the pressure for a good amount of time on its own. Check for air coming out of the crank vent hose or the oil fill hole. Also dont overlook the simple things like your premix ratio. try 42:1 or 50:1 ratios of gas to premix oil.

G'day Murray! Could actually be a couple of things.I'll try to eliminate them by degree of difficulty and cost. first up make sure your carb jetting is correct and nothing has come loose inside the carby to cause an overly rich mixture.Is your air filter in good condition ??.Lets presume you've kept up a good maintainance regime on ya beast.Next i would check your radiator levels to make sure the tank levels are not dropping as this will indicate leaking fluid possibly via a head gasket leak into the combustion chamber , then i'd go for the right hand crank seal,especially if your gearbox oil level is low , thats the rather large seal behind the drive gear on the end of the crankshaft on the clutch side(right side sitting on bike).You'll have to remove the nut,check for an "L"mark indicating left hand thread,remove the gear and spacer and there may be an "O" ring behind the spacer as well,milk it off carefully,prise out the seal with a.....Heh you guessed it....Seal puller,not the type our eskimo friends use...HAHAHAAAA...THEn tap in the new seal with a socket that fit the outer bearing surface of the seal keep it squared,and then.... SSSHHHHMMMOOOOOOSSHHH...YOUR DONE.You really need to access how much work the engine has done,when was the last top end rebuild done etc???.Could be worth while doin the whole lot in one hit if you've got the coin..Oh yeah , here's the part number for the Winderosa seal kit,its: 822326. hope i could help ya out ..MUZZA.Goodluck...regards..Tilleydog

White smoke is coolant in the combustion chamber, blue smoke is oil. If you're seeing white smoke and oil from the tailpipe I would guess a head gasket problem, but you'll have to pull the head and find out for sure.