bogging acting like choke is on
 

my scooter has been running great then I think I might of got some premium gas with ethonal.this is whats happening.its sputtering like the choke is on or a bad plug till I hit a down hill and once it gets to 8000 rpms shes fine and will do over 50.i have a bbk,pipe and jetted to a 80.my pipe always wakes up at 8000 rpms but it cant get there unless I get a down hill and once it hits that mark it will scream until I let it go below the 8000 rpms.it starts right up also but sputtering till those rpms.changed plug also

Could actually be the choke not working right if you have a carb with electric choke.

Otherwise sounds like something in your carb is either out of adjustment or possibly clogged. I would check the pilot jet first.

Also an 80 jet sounds a bit small for that setup, how do your plugs look? Nice and brown, or white?

I fixed it.it was the carburetor boot to the air cleaner had a crack in it.i tried a 85 jet and ran terrible the 80 is just right.actually the 75 worked fine but more rpms with the 80 and my gas mileage sucks I also have 1500 rpm clutch and torque springs

Ah yea that would do it.

Your carb is probably different than mine, so I guess it makes sense that the jet size would be different too.