mine does the same thing. my buddy doesnt have his air tubes and his runs perfect. i have been battling this problem for a while.

 

try running the bike in the wind lol... with the choke fully on.. sorry but it sounds funny

 

About Jetting...

With a K&N I would have assumed you were already at Stage I...if your carb is stock with a K&N surely you are getting too much air and running lean at high speeds/winds.

But...your shop is right...once you jet you will have to tinker all the time: hot, cold, wet, dry, high, low...

 

when i first got my bike i put a K&N on it and a yoshi without jetting it and i never seen a difference. no problems at all... a K&N doesnt give you that much more of a air intake to cause problems like that..

 

Interesting Mr.Bond I never thought about this.Im having the same problem.My bike sputters and studders at various speeds.This problem evolved after I made the jump into streetfighter world.I've actually been thinking it was the radiator because it's a huge flat brick wall and I thought the wind was pushing back on the bike and overpowering the output of the engine.Im gonna tape up one of the intake tubes to the airbox and see what transpires.

 

alpine, where did you get the idea my choke was on?

so it sounds like i should get it rejetted.

bindel- do you have the stage one jets i need? i'll buy them off you if so. just let me know!

 

sorry alpine i re read you post.. makes sense but i haven't tryed it yet.