1980 GS400 - Where the hell does this hose connect to?

[Guest]

Please help! Clearly I'm in over my head. I have pulled out my carbs to clean/rebuild but now after putting them back together an back on the bike I can't for the life of me figure out where one hose attaches to. It comes of the right side carb at the back. It's not the fuel line or the vacuum hose. Sorry for the crappy picture. It's really tucked in there so it's hard to see. Any help for this newbie would be appreciated.



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[Steve]

I don't know how that bike is set up (we dd not get them in the US), but there should be three hoses connected to the carbs.
1. Fuel hose. Will connect to a T between the carbs, just above the float bowls.
2. Vacuum hose. Will run between the petcock and a nipple that is probably on carb #2 (right side). That nipple will be on the outlet side of the carb.
3. Vent hose. Will connect to a T between the carbs, just a bit higher than the fuel T. I'm not really sure about this one, because it would tend to occupy the same space as the throttle cable linkage.

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[Oldspooneye]

I don't know how that bike is set up (we dd not get them in the US), but there should be three hoses connected to the carbs.
1. Fuel hose. Will connect to a T between the carbs, just above the float bowls.
2. Vacuum hose. Will run between the petcock and a nipple that is probably on carb #2 (right side). That nipple will be on the outlet side of the carb.
3. Vent hose. Will connect to a T between the carbs, just a bit higher than the fuel T. I'm not really sure about this one, because it would tend to occupy the same space as the throttle cable linkage.

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It may be the same as the 1980 GS450 but I'm not positive about that. I have the fuel hose connected to a T between the carbs and the vacuum hose connected to the right side carb. The third hose may be a vent hose but it's only connected to the right side carb not to a T between the two. If it is indeed a vent hose, what does the other end connect to?

*edit - there is also a short hose that runs between the two carbs but it is not a T with something else connected.

[Oldspooneye]

I found a diagram that says it's a breather hose. Can I assume that means it doesn't attache to anything and just runs towards the back away from the engine?

[Steve]

Your "breather hose" would be the same as the "vent hose" that I mentioned. It does not attach to anything execpt the carb. It is the atmospheric reference for the float bowl, so it should end in relatively calm air. See if there is a loop on the back of the airbox or a loop on top of the filter housing under the seat that would hold the hose in place.

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[Oldspooneye]

Thanks Steve!

[Runeight]

The vent tubes on mine connect to the nipples on each carburetor on the inside. They then run back to the top of the air box. There are two bosses molded into the top of the air box where the vent hoses rest.