Topic: Honda CB350 Four running rich with stock setup - why?

[thormeyer]

My CB350 Four from 72 is running very rich. It has stock exhaust, airfilter and karb. I have had the engine rebuilt (new rings, top end done and new gaskets - have done compression test 12 bar (170 psi) ). I have clean the karbs, and before the rebulid it ran better with no fouling of the plugs. Now the plugs are black and sooty even with the air/fuel screw out 2 turns (stock 7/8).

Any ideas to why it is runing rich???

best regards

Thor Meyer

[robvangulik]

Is the airfilter clean?
And is there nothing under the seat blocking the entrance to the filter?

[flybox1]

^^ +1

Did you install aftermarket float valves, and/or a carb rebuild kit(including jets)?