carb interchange q

[muttblbc]

im trying to bench test a 73 cb750k engine that i just got through rebuilding, but the carbs for it are in a different area code. i have a set off of a 78 750k, does anybody know if these will work without having to rejet or tweak too much? thanx!

[Spitfire]

Hi,
    The 1978 carbs are a different model to the 73 carbs, I think they are a larger bore (28 mm) with 110 main jet and 35 idle jets, and are fitted with an accelerator jet.
The 73 could have 120 main and 40 idle, so they are probably not usable as they are. The 78 engine may have bigger valves and definately has larger carb boots.
With the latter boots and re jetting you could probably use the carbs, you will have to find a way to fit a choke cable as well as the later bike had a choke lever on the handlebars.
Or look for a set of carbs for a 73 on eBay, and sell the ones you have..

Cheers

Den