Carb Hoses

[Poot]

Hi all,


Just a quick question here...


on the carbs of my 1980 850, there are some hoses I'm replacing. I'm not sure yet, what the length/diameter of hose I need yet is, (phoning dealer tommorow) but more importantly, am not too sure where some hoses go.


I know where the thick and thin fuel lines go, but am wondering where the hoses going on the plastic "T" s inbetween carbs 1-2 and 3-4 would go.

they are the fuel vent lines, but I dont know if they link together, or just dangle into thin air(i.e. venting)?


[pooot]

[Anonymous]

they dangle in thin air.

at least mine do

[Poot]

that makes it easy! thanks :roll:

[bwringer]

They just...dangle.

On my GS850, they go up and over the airbox and dangle somewhere behind it. You want the open ends to be somewhere where they're not going to get a lot of air rushing past. You wouldn't want any weird effects from a partial vacuum on the vent hoses.

I think you also want them to loop up from the carbs before ending with the ends pointed down. That way, water or gas can't accumulate and block off the hose like a a sink trap.

To be honest, I'm not entirely sure exactly what effect this would have, but I'm sure it wouldn't be good.

[Anonymous]

Yeah, those tubes vent air at atmospheric pressure to the bowls so that there is a pressure difference between the bowls and the venturi, which in turn motivates the gas to enter the airstream by way of the various jets.

A fun experiment, if you feel like getting intimate with your GS, is to blow into them. Just make sure the engine side is facing you or gas will get all over you. I did it one day to verify that the tubes did, in fact, do what I thought they did.

In theory, any pressure effect on these tubes will affect mixture. Higher pressure will "push" the gas in the bowls out, richening the mix; lower pressure will "draw" the gas back, leaning the mix.

On my GS, they run over the airbox and kind of hang out in the dead space above the tranny but below the battery. This spot is pretty much ideal, because there is not a lot of airflow and not a lot of heat. Either one could throw off the pressure.

[Poot]

if i dont have luck at the dealership, do you guys know what the diameter of the various hoses are????


thanks

[Anonymous]

Not off hand, but I'll be happy to measure. Mine are from a GS1100GK, they're 38's I think.