so just to be sure, from what i have read, i am supposed to have two throttle cables on a 1978 cb750k(push pull), this beast that i just bought to do a cafe build (it is a bucket, been sitting for 15 years or so) only has one cable but it has a spot for the other, did some only come with one cable or has someone taken the other off at some point in time. i'm asking because i need new one(s) and not sure to get the two setup or one( i see listings for both setups online) thanks for reading and any expertise is appriciated!!!!!!
It had two. The "B" return cable is a safety feature and does nothing if the throttle is otherwise in good working order. It is along for the ride.
If anything in the "A"cable fails, like it gets hung up, the return spring fails etc, the B cable allows you to force the carburetors, or at least the throttle butterflies, closed. Your carbs have the chance I think of the CV slides to hang up anyway. Very remote possibilities.
It has been the subject of many threads here, whether one can be comfortable running an A only setup or not. It is the sort of discussion as helmets, lights on, etc. Sure you can do without it, but should you. Personal choice in my book. The CB750 introduced the dual cable setup to most of the civilised world IIRC. others may have had it, but not in the volume of the CB750. The pre-K1 models had a single cable setup. Many bikes, customs, etc still do.