Motorcycle Repair: Bike cutting out, full throtle, yamaha xt600

Question
I have a yamaha xt600 and am having problems with it cutting out at speeds between 55 and 70 mph. It acts like it is starved for fuel. This mainly happens when close to full throtle but not always as in the case of going only 55. I have taken the carb apart and cleaned along with ajusting the float. Also adjusted the throtle valve so it is horizonal at full throtle. I have a repair manual that came with the bike that i have been following. The book does not give spec's. for the pilot air screw setting or the fuel metering screw that is ajustable under the float bowl. Any ideas would be greatly apprieciated.

Answer
Hi Phil.
 Before you go adjusting the mixture, check the plugs after a hard run.  Are they fouled or burned up?  Are they whitened from excessively lean fuel?

You could have a fuel flow problem in the fuel line or fuel valve.  Possibly something loose that keeps clogging things or something that is restricting fuel flow enough to starve the engine when running at higher speeds.

There is the remote possibility of a short in the ignition system somewhere as well, but that is unlikely.

Check the fuel system and let me know what you find.
Good luck.
FALCON