I recently purchased a junior Sprint car with a 1984 Honda 200m motor. We rebuilt the car from frame-up. Right now we are having motor issues where the motor seems like it has a rev limiter at around 3,800 to 3,900 RPM. I know the motor does not have a rev limiter. I am not a novice when it comes to Motors. I have been working on them for 20-plus years, but this has me baffled. the motor has a 12 to 1 compression piston in it I am running VP Race Fuel it has a oversize cam and a 34mm carburetor. I bought the car in pieces and when I first put it together so we could test drive it it seemed to run fine other than the idle was weird it seemed lean and only wanted the idle high. so I took the carb off soaked it cleaned it put it back together and it did the same thing. I purchased another carburetor brand new put it on and the motor ran the same way so I assumed it's a jetting issue. the carburetor that came with it had a size 40 pilot jet and a size 96 main jet the needle is set in the center position.the air screw on both carburetors did not seem to make a very big difference when I adjusted it either way. I tried putting a larger pilot jet in the original carburetor and it seem to affect the top-end more than it did the bottom end. it made the high rpms worse. I tried running a smaller pilot jet and it was worse then when I had the 40 in it. I've tried running a larger and smaller main jet and the original Main Jet seems to be the best. I'm getting plenty of fuel to the carburetor. I'm getting plenty of spark. I have tried adjusting the needle up and down but the center position seems to be the best. And I'm out of ideas. any help on this would be great.