Topic: Alternative fuel petcock cb500 k1 for cb750 carburators

[Korven]

I fitted Cb750 carburators to my cb500 k1. However the fuel petcock on my tank (K0,K1 left sided petcock) its hitting the carburators. I knew of others fitting a cb500 K3 tank instead since that has the threaded one on the right hand side instead. If anyone know of any alternative model petcocks that might be slimmer/flatter or that might fit for this please holler.

Easy way would be to get a k3/550 tank but...

[bryanj]

Dont know of anything that fits the same way except the original, all 500/550 tanks are getting difficult and expensive now.

[Little_Phil]

Think all 500/550/4 petcock are on the left side. Are you sure your K1 has the original tank. (Has the same petcock is the 750) Later tanks on the 550s look the same but have a stub screw thread and the petcock hangs lower. 550K3 tank (yes LHS) petcock outlet is pretty close positionally to the early 500s.

[69cb750]

please holler.

CB500 carburetors are the best carburetors for a CB500.
The CB750 carburetors are designed for 750cc of air flow and will work poorly on a CB500.

[Korven]

please holler.

CB500 carburetors are the best carburetors for a CB500.
The CB750 carburetors are designed for 750cc of air flow and will work poorly on a CB500.

That might be, although ive read about people using them as means powering their hotted up cb500 in the 70's. (mine is a 592).
But you are right there is another problem. i can only open the throttles about 80-90% before they hit the tank. Was gonna be a fun winter project to try and get it work. im just gonna go with 500 carbs because paintjob is already done.

Edit: ive acctually seen a bike with this setup. gonna see if i can find the pictures.

[jonda500]

I briefly ran 750 carbs (with pods, removed from a 77 550K) on my 500 - with the appropriate size main jets you can definitely get good full throttle performance, but I was told that with 750 carbs used the mid range would suffer so I decided to get the original carbs refurbished,
John