Fast Idle problem

[71prostreet]

Was wondering if anyone had any ideas, I built a new motor for my shee, new crank, pistons and cylinders bored and honed. The problem is that everything I see about jetting says do the low end then work on 1/2 to wot but as it is a new motor I really don't want to go past half I only have about 25 minutes of run time on the motor. The low end is perfect no problems at all, But when I start to beat on it a little to do some short blasts to 1/2 throttle when I let off it kind of fast idles or revs up a bit, If I tap the throttle a little it goes right away. I do know the carbs are closing, Kinda thinking it is maybe a lean main jet problem. Any help would be great. The carbs I have are the Keihin PWK 28MM I'm not sure what main jets I have they have no numbers on them. The pilots have 60 on them some people say that's to big but the low ends runs great and the air bleed screws are only out 1 turn. think the problem I'm having is main jet problem or something else?

[jbooker82]

1/2 throttle would be the needle. Are you sure you dont have an air leak. They will cause a high lingering idle.

[71prostreet]

I tryed The carb cleaner method and did not find any leaks, The problem does not seam to happen if I free rev the motor just sitting in neutral. It doesnt even rev that high just a little bit off idle like a really fast idle. The motor when I got the shee had a burned right side piston but the left was fine and in really good shape. I dont think that just by going 1/2 mm over on the cyl and piston I would really need to jet for that right? the motor does not even seem to get that hot. any idea if a banshee can be tuned by exhaust temp or if there is any good temp number a shee should have at the head,cyl or exhaust? Thanks