ive noticed this in the last week. whenever i get over about 65 i dont have any power, in the lower gears at higher rpms i still have power but when i shift into 6th its like the bike loses almost all acceleration and the engine tops out at 6,000 rpms, but if im in fith it acts completely normal and will do 7k plus
fuel starvation
Or slipping clutch.
How would the clutch or carb know if he was in 5th or 6th?
For a given torque at the wheel, the torque at the clutch is greater in higher gears. A worn clutch (or weak springs) will slip at WOT in higher gears because of the reduced mechanical advantage.
I don't know about the carb....
Upon further thought, if rpm just stops rising at 6000, it's not the clutch.
Are the throttle plates opening all the way?
is your choke on?
could be your jets are clogged or the slides are sticking down.
I say you are a bit lean or have a semi-clogged main jet. I rejetted with a buddha jet kit for a stock bike and it is better at 6000RPM. Of course you have 3 circuit carbs, but I think a semi clogged main is the culprit. I bet you don't have quite enough vacuum signal to get good flow in the mains in top gear once you crank the throttle open in 6th, but with higher engine speed, and a gearing change, you might be ok in 5th.
Free advice is worth what you paid for it though.
takes more power to go above 6k in 6th than in 5th. Limited gasoline supply wont support above X rpm in top gear, or X + 1000 in 5th. This guess was a long shot. I admit.
The carb comments would cover my "not enough gas" idea.