Motorcycle Repair: Motorcycle loss of power, yamaha xj600, carburator

Question
I own a 93' Yamaha xj600 and it sat for 6 month before I purchased it. I rode it pretty hard when I bought her and now she has performance issues. Sometimes when I accelerate, over 6000 rpm I lose power and the muffler makes a funny noise like its blowing its nose. Like air passing through a tube balloon with its end cut off. I love riding so its really killing me to stay off the bike. If you could help me figure out this problem I would be most grateful.

Thanks,

Darius  

Answer
Darius,
 You could have a significant exhaust leak that is causing this, carfully feel around the whole exhaust system while running.  Other than that you may have a broken baffle which is not letting the flow pass efficient ly.  Both of these things can be easily repaired by dismantling the system, replacing any broken or leaking components.  Other than that you could have improper timing (not likley in you model, it's prob. an electronic ignition, no points to adjust), an improperly adjusted carburator or leaking intake boot, a bad or improperly gapped spark plug or bad coil.  Sorry I can't be more specific, hard to tell w/o being there to here it.

-Mike