89 250s runs but cuts out at high r's
 

ok i have a 89 lt 250s bored and rebuilt top end 20 over brand new carb mikuni vm26sc 22 pilot 112 main new CDI coil voltage regulator bike starts 1 or 2 kicks idles well heres the issue rev the bike up and it cuts out like its hitting the rev limiter or for those with newer quads its like you left the emergency brake on which limits the rpms.im rattling my brain trying to think what the problem is any suggestions would be helpful

Main jet clogged or not big enough?

sounds like possibly electrical to me, new cdi coil voltage regulator???