I have the same problem on my '02 zx6r. I talked to a guy with a 02 zx9 and he has the same problem too. apparently, the can is not moved out far enough to clear the swing-arm all the way. I think this is a design flaw on Kawasaki's behalf, but that's me, because it seems that all kawasaki's have this problem. In my eyes the swing-arm "should" have full motion up and down. I have a full muzzy system on my bike and the guy i talked to also had a full muzzy system. The guy with the zx9 pointed out a very good thought, our bikes weren't meant for doing stoppies. I don't think there is a bike that was meant for doing stoppies. Our best bet man is stiffen up the rear all the way. It will suck to do stoppies on, already cracked my nuts twice coming down from them. But hey my pip is seriously fucked, and it sounds like a god damn freight train is coming down the street, "bwaaaaaaaah!"
But until we can find a popular fix for this, then we are stuck, so far only a small few have come out and said anything. And actually the guy with zx9r wasn't even aware he had a hole in his muzzy can until i came out and said something. He was pretty pissed off about it. N-e-ways bro, I'm gettin a new micron exhaust, full system, and this time i am gonna fabricate a damn spacer systen for it so it doesn't hit the swing arm. I even though about fabircating my own high-mount muzzy system.....but i'll have to take som time to design that one....
That the deal seal!
A wise man once said worrying is like sitting in a rocking chair, it gives ya something to do, but doesn't soplve the problem!!!