Fuel not getting to carbs?



Friend and I are working on cb350. It started up when we got it but wouldnt stay running and wouldn’t idle. So we rebuilt the carbs, replaced pet cock, and fuel lines. We cleaned gas tank and changed the oil. No dice.

We checked spark which is good. Then we decided to check the fuel bowls which are quite dry. We took the fuel lines off the carbs and noticed that only one or the other seemed to be getting a steady stream or fuel and the other sort of just dropped. If we plug one side the other flows quite well. The lines are new, don’t see any blockages.

We are at a loss as to what is happening and any help is appreciated!


Well-Known Member
That's quite normal. When the carbs are not connected, it seems that fuel will flow from one pipe or the other but rarely both at the same time. I suspect that when fuel starts to flow in one pipe, it actually draws air in through teh other one, so only one will flow. Pinch off one and the other flows.

The question is why are both float bowls dry. Sounds like no fuel getting into the bowl. Start by attaching a length of fuel hose to one crab and blow into it. Does air flow into the bowl? Then rotate the carb as you keep blowing and you should feel the point where the float causes the float needle to close.

You probably have a sticky float or sticky float needle. Look at those again.


We will take another look. We each did a carb and my float definitely was not as 'bouncy' and the needle does go up and down freely but I also feel like its not as freely moving as the other side.

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