hey everyone i have a 01 yamaha raptor 660 it has run great for me. then one day i changed the oil and took the spark plug out to inspect it. ever since it has been blowing alot of smoke on start up then disappears. the oil level is at a good level. anybody have any ideas?

 

sounds like the valve seals are going bad

 

if its white smoke you are burning coolant, then i would suggest a bad head gasket, if it has a bluish color to it, it is probably valve stem seals

 

If it's just upon startup it sounds like a blown head gasket.