the best jetting for the klx is 48pilot 162main drop the needle clip 1 position, also wire the accelerator pump and run the mixture screw at 2 1/2 turns out, change the leak jet to a 55 or 60 (this is the small jet in the float bowl) this is the jetting used by MSC Kawasaki Off-Road, the klx can go backwards if its to rich on the main so it can be a bit tricky to get it spot on! the MSC bikes run Barrett Exhaust with a Uni Filter.
hope this helps