1983 HONDA QR50 HELP

[ZacKx450]

Hey guys i recently picked up a 1983 honda qr50 2 stroke, has had the frame rewelded and resprayed as well as top end rebuild, when i got it the main jet was blocked, pulled the carby off doused it in carby cleaner and blew it out with the compressor, put carby back on and she fired first kick, the issue i have is i cant get it to idle smooth its either ringing its neck off or dies out after you rev it up, have fiddled with the idle screw and i can get it to idle nice but once you rev it it revs hard as if the valve is still open for a few seconds then will either settle down or stall out, also im not using the oil injection pump just premixing in the tank, not that it should really matter? any one awesome with these bikes or the carby and can point me in the right direction on my next step?

also if anyone knows where i can get a new set of plastics seat cover and just all parts in general that would be awesome!!!