Motorcycle Repair: Motorcycle loss of power, yamaha xj600, grateful thanks

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
Hi Darius,

In all my career, you're the first to describe a problem in such a manner. : )

It's difficult to diagnose exactly what is happening. I suspect a carburetor problem, but it could be an ignition related problem.

Can you describe the appearance of the spark plugs?

Respectfully,
Mark Shively