there's no "choke circuit" it's manual choke. is the choke on or off?
you probelby need to lower the needle by raizing the clip up 1 notch. also what is the mixture screw set too? it should be turned in till stops and then turn out 1 1/2 turns. and start from there. adjsut the idle screw on the side by turning it out slowly to lower the idle.
does the bike smoke a lot?