January 25, 2010 10:53 PM PST
Intake leak, exhaust leak, bad plug wire, loose battery terminal, poor connection at coil, improper A/F mixture. Pretty much listed in order of likelihood
January 25, 2010 10:53 PM PST
Agreeing with TheX , Usually caused by something leaning out the mixture.Assuming this bike has a carb and it happens after the bike is fully warmed up check/replace the carb intake manifold seal/gasket. This was the fix on two different bikes, one mine and one a friends.
January 26, 2010 1:46 AM PST
Hey thanks for pointing me in the right direction, it is a carb, I'll start with the gasket and work my way down the list if that doesnt do it
January 27, 2010 2:15 AM PST
Yep, sounds like an intake leak to me too.
January 27, 2010 5:55 AM PST
Be sure to let us know what you found, may help someone else out.
