bike wont idle after cruising surging rpms

ive checked everything i could possibly think of for leaks, tore down my jug and replace all gaskets and used a bit of gasket seal on each to help seal it. checked both sides of the motors Bearing seals (no gasket seal put on these) there fine no oil/gas in the case or on the out side of the seals.

Also when i start to get near the top of my rpms (doing the math im getting around 6300 rpm at 32 mph) im using a 41t sprocket and can get to 32 mph but getting to 32 is kinda rocky anything over 27 mph and the motor just doesn't feel like its running right. it seems like somethings starts releasing compression somewhere or something.i start hearing an extra noise that's different than the carb and exhaust like an air leak but cant tell from where.

any help would be great been dealing with these issues for almost 2 months now and im stumped even had 2 of my buddy's take a look at it and there just as stumped.

is it possible that my head not making complete contact all around the jug could suck air in and make a lean condition its the only thing i can think that's happening ive got a bit of oil residue coming out from 2 spots on my head. i haven't lapped the head yet.

Already replaced them first thing i did. and yeah im gonna lap the head before i ride it again.

Thanks for the help ive been threw everything else and read as many things on the forums i could find before i posted. this just had me stumped on what was wrong


what grit sand paper should i use ?