Found this elsewhere : "You may also want to richen the pilot mixture by adjusting the pilot screws or going up one size pilot jet as the pilot circuit may be a shade lean from the factory."
Had the bike sat for a while? Could there be clogged pilot jets?
Do you still have the stock can? If so, swap that on and see if the problem goes away.
Much easier to isolate the cause before trying to solve the problem
Bob