Topic: 1981 CB650 Carb Question

[annerstine]

I just bought an 81 CB650C, the bike cranks up but when you turn the fuel petcock to on the carbs start spilling gas. So i pulled the carbs off and I noticed that it looks like there is one missing hose between carbs 3 and 4 and the hose between 1 and 2 is rotten and almost coming off...What does this hose do? at first I thought it was the fuel distribution hose but now I'm wondering if it has to do with the vacuums. Any advice would be greatly appreciated!

[harisuluv]

Those are just tubes that equalize pressure.  Example (shotgun a beer:  the second hole allows it to empty or fill faster, in this case the fuel level in bowls)

At the bottom of the bodes (or at the top of your picture) there are clearly  two aluminum tubes between the carbs.  The smaller one is the accelerator pump circuit.  The larger one is the fuel line.

[annerstine]

thanks for the reply harisuluv! so would the fact that the tubes are rotted and/or not missing cause the bike to run poorly or have anything to do with the carbs spilling gas?

Also, I posted some more pics just to make sure we're talking about the same thing, notice the rubber hose missing from the 2 protruding metal cylinders.

[harisuluv]

Yes we are talking about the same thing.

Your problem is due to the float and valve not shutting off gas flow.  Therefore, gas keeps coming in until it reaches the overflow level and then it starts to drain out.  For your bike, this can be fixed with new float valves.  You won't need to set the float height because those floats have no adjustment (plastic).

[SOHC4 Cafe Racer Fan]

annerstine,

Don't let hariuluv's avatar fool you.  He doesn't just rebuild carburetors, he makes them like new.