[avidis]

runs great for 5 minutes, than keeps slowing down and speeding up,runs great for another 5 minutes, then it does the same thing again.

 

[KevinFT]

Same thing just happened to my 1996 GSX this year. The problem with mine was that the spark plug caps were faulty, causing only one of the cylinders to fire half of the time. Also my impeller was chewed up pretty badly. But im guessing only one of your cylinders are firing.