Well, I took an interesting approach to solving this problem. Last week I took off the carb and cleaned it real well, making sure the pilot jet was not clogged. Everything looked okay but when I bolted it back together, and started it up, the engine continued to race.
Rick, the plug is black, but I know it is running lean - I just don't let it run long enough to turn the plug a light tan or white.
So on Saturday I did what any KX500 owner would do, I went out and bought another one! I found a 99 that was in VGC and had some nice extras with it, both on and off the bike. I got it for $1575, which I thought was pretty good price.
I took the carb of the 99 and put it on the 01, just to make sure the carb wasn't the problem. The 01 engine still raced with the 99 carb. I guess it has to be an air leak somewhere, so I am going to try a pressure test in the near future.
So now I have a one KX500 that runs great, and I can take my time fixing the other one, and still get my KX500 rush once or twice a week.
Is there some sort of open bike support group I could attend? This is my 6th KX500 over the past 10 years. "Hello, my name is Ben, and yes, I have an open bike problem..."
--Ben
2003 Yamaha YZ450
2001 Kawasaki KX500
1999 Kawasaki KX500