2004 Honda Ricon 650 no power in 3rd gear

Hello everyone I have a problem with my rincon. I just replaced the cam shaft and timing chain and carburetor and did an oil change. It runs beautifully except now as soon as it hits 3rd gear it hits the rev limiter and loses power, 1st and second gear are flawless. Hits about 38mph till 3rd gear and then it hits rev limiter and drops speed. I changed the shift solenoids and no change. Would the oil pump cause this symptom?