goin nuts Honda (revised)

[Ejh]

Hello everyone,i'm a newbie to the froum Thank ya'll for haveing me here and i'm happy to be here. My brother posted a question (going nuts Honda 750 plese help) just out here to ask for more help. I have a problem with a 81 cb 750 c that she will not behave above all efforts to calm her down. In the past i've changed the motor from it's original to a 79 cb 750 k along with it's carbs and exhaust, since then i've changed the coils and the little spark boxes that control them from a 83 cb 750 f model. The spark boxes where not melted (as they all do) so i think there o.k. The coils fire up the bike so i think there o.k. The current problem is that when started you can whack the throttle and when she comes down she'll hover at 2k rpm's until you go after the idle speed screw to bring her down,then she'll die as if the idle is to low. If you restart the bike and play with the ide speed screw to make her sit on 1k rpm's she will then whack the throttle and it's back to hovering at 2k until you back the idle speed screw out and she die's. The rubber boots between the carbs and heads are brand new from Honda and the clamps where tightened till tight with some space between the ends (aka not over tight). I,ve run the bike without the fuel cap on the see if the vent was screwed up still the same thing, there was a fuel filter inline took that out still the same thing. Hooked up sychro gauges to see how far out they maybe their within 2 hgs of each other, idle mixture screw have been set from 1 1/2 turns out to 2 turns out same thing. If you have any suggestions they would be appreciated.

[pinky44]

Have you tried replacing the throttle cables ? as they might be sticking.

[HondaTech68]

its running to lean you either need an idle drop done or a carb clean. I would start by doing an idle drop wich is an adjusment of the fuel mixture screws in order to do it correctly you need a tack and a special adjustment tool so you wont get burnt while doing it. I can give you detailed instructions if you want.