Motorcycle Repair: FUEL, valve seals, white smoke

Question
HONDA CB900CUSTOM,TOP END GOING UP HILLS-60MPH.I CLEANED CARBS,PETCOCK,TANK,AIRFILTER K&N,CHANGED PLUGS&WIRES.PLEASE HELP,DISCOURAGED.   RAY

Answer
Hi Ray.
 What else have you done with the engine?

 Are the valves and ignition timing within specs or overdue for tune-up?

 Has the mixture been tampered with?

 Are the valve seals and rings good?  Is it blowing white smoke?  That would indicate bad rings.

 Are all of the cylinders firing?  You could have bad coils or a short in the wires between the power and coils or bad connections in the circuit.

 Check with those and let me know what you find along with anything else about the problem that you can think of.

Good luck.
FALCON