vacuum port on no.2 carb 1980 gs1000g

[Anonymous]

I just bought this 1980 gs1000g and the pick up on it is terrible what is happening is if you crack open the throttle just a little it seems to work ok but if I try and crack it wide open it just bogs out so I figured that the carbs needed a good cleaning so I went ahead and pulled the tank ,airbox and carbs off and I was just getting ready to open up the carbs when I noticed the vacuum port at first I didn't know what it was but I did not pull any hoses off of it so I found out where the vacuum hose came from, the back of the fuel petcock . So I am wondering if that hose was not connected to that port on no.2 carb what would be the effect could this be the cause of the problem, I just figured I would ask the experts before I rip the carbs apart or put everything back together again.....thanks....mark

[Anonymous]

vacuum port

the fuel petcock has a diaphragm inside that is vacuum actuated, when the bike is not running there is no vacuum and the diaphragm shuts the fuel flow off, this is a good feature as it avoids a crankcase full of fuel. If that vacuum line was off that would certantly cause a fuel flow problem and might explain your symptoms, also if that line was off and your still getting fuel flow you might look into getting a new petcock or a rebuild kit

[saaz]

The fuel would not flow except on the prime setting, and there would be an air leak into no 2 cylinder leaning it off. The bike runs terribly like that, trust me!

[Anonymous]

I do have a petcock rebuild kit on the way because it is leaking when I took the tank off it kept coming out of the petcock not full flow but a pretty consistent dripping .....mark