I just bought a 99 superhawk and the bike just developed a problem. It runs well but at all rpms but any time spent for more then 30 seconds between 45 and 5k rpm the bike seems to develop a bad miss and hardly wants to run. After riding it for another 3 minutes and getting off the highway while waiting at the light it cleared up on its own. Been testing and like clockwork it starts running terrible with any time spent at that rpm range. The previous owner said he put a new petcock and bike has 24k miles

 

Make sure the vacuum line going to the petcock goes to the fitting on the side not the one on the bottom.

 

Going to take it apart tomorrow and check it out thanks

 

Nothing to take apart, its a visual thing.. The petcock has two nipples (lol yes I said nipple)
The one on the bottom is not used, it is solid, just there for other applications this part is used on.
The only "port" is the nipple on the side.

so just take a gander, or feel for the........yes, feel the nipple...

 

Agree with the suggestions made but if that item checks out, then check for a pinched vent line from fuel tank. (The complete shop manual is posted in the knowledge forum and you can view correct hose routing diagram in it.) Basicallly agree it sounds like fuel starvation from what cause TBD.