rev's on it own then diesels after kill switch ins engaged

[BigMatt]

first off my bike has FMF fattys, trail ported & polished, wiesco pistons, and I just advanced my timming +4 and am running klots 40-1 on 93oct. well just after advancing my timming I took my bike out it idle great started good but after it got warmed up it would go in sperts where it would rev up real high for about 2sec's then return back to idle after burpping the throttle, so today I wanted to find out what it is so took it out again, road great and once fully warmed up it did the same thing except now its not returning back to idle. now every time I start is up it revs real high and I am afraid of blowing the motor and when I hit the kill switch it dieseled for a bit. I checked my cable seems fine, took off my pods and looked at my slides they are working right and synced. my next guess is a air leak but not sure where to look? is there a leak down tester you can buy for the banshee? or do I have to make my own like the guy on this site and how well does that work? also I did switch out the boost bottle that came with the bike for a cross over tube but the boots seem to be in good shape, could this have anything to do with my timming? what are all the seals that could cause this? thanks

[AKheathen]

yah, sonds like lean/airleak.....it should calm down when you pull the choke.........you pretty much have to build it as far as i know, currently. mabey a sponsor has pre-made ones, like fast. check your carbs where they clamp into the intakes. mine were glazed up once, and it reved to the moon while i was ridding........i scuff them, or make sure they are still scuffed good every time i put my carbs on now. look @ the bottom of the intakes for cracking. pry the carb around to expose cracks. make sure there is no water in the bowls either, and that the jetting is good and set for a hot engine, too.

[badassbanshee479]

fire the bike up and grab a can of carb clean... spray around the carb boots, the base gaskets and the crank seal behind the stator..... if there is an air leak you will hear the engine change tones.

I f I had to guess, it sounds like the crank seal behind the fly wheel was damaged when you advanced the timing..... did you have to heat the flywheel up to get it off? did you use the correct puller to remove the flywheel?