I recently just bought my old bike back from my friend that I sold it to and it wasn't running when I got it back. He has no idea what's wrong with it. I replaced a few fuses that were blown, one that he had too small of a fuse in. the rectifier went bad and started smoking so I replaced that, then had no power again. took my battery in, found out that was bad so bought a new one, now I can get it started but it will only stay running if I hold the throttle down otherwise when I let it go it will die. Also when I get to about 5-6rpm it starts to struggle. Please help, wanna get a few rides in before it gets too cold!

 

Sounds like you need to pull the carbs and clean them out. You're not getting onto the main jet and your idle circuit is only partially working. Choke cable probably needs to be set too.

 

had pretty much this same problem when i bought mine the guy had it setting outside for a while, had to clean the carbs out and run seafoam threw them for about 2 tanks and re-adjusted the idle and choke cables its runs pretty good now still loads up everyonce and a while i think i need to resync the carbs now.