I bought this 1998 KLR about a month and a half ago. From the first time I tried to really wrap it out, it starts missing in 3rd, 4th and 5th between 4500 and 5500. It has a jet kit with a Supertrapp exhaust and an aftermarket filter. I've tried replacing the petcock, fuel lines, vacuum lines and I even replace the coil. I can't get it to run smoothly under hard acceleration. It still coughs at 4500 to 5500 RPM in 3rd,4th, and 5th. I can accelerate hard from 1st to 2nd and it will be smooth up to 7500 rpm. I took off the carburetor and cleaned it with carb cleaner. Nothing has worked so far. I would appreciate some insight. Thanks.