GPX 250 hits 10000 revs then misfires back to 7000

hi guys n gals, i just bought a GPX 250 and when it gets to 10000 revs it misfires back to 7000 can anyone tell me why, thanks

no.

Because trying to diagnose motor problems over the internet is just a guessing game for most people. Take the bike into a mechanic and have them tune it up. During this process - they should find out the problem 9 times out of 10.