1977 GS400 Vacuum Hose Routing

[Guest]

Hi, sorry if this has been answered before but I have not been able to find a good diagram or photos of where the vacuum lines should be running to from the petcock. I am trying to confirm that the hoses are in the right place and am worried about messing it up. I found the BassCliff post about hose routing but the photos are no longer available to look at. On my bike I see a vacuum line running from the petcock to the lefthand carburetor, should there be any other vacuum lines? Does anyone have a photo of the hose routing or a diagram where it shows where the vacuum lines should go?

[rphillips]

Doesn't really matter, as long as no kinks or sharp bends that could affect the vacuum to the petcock. I'd route it so it won't be an eye sore...Hey, welcome, a lot to be learned around here.

[Guest]

Thank you! Got my bike last week and this forum has been a lot of help in learning more about it and what maintenance is in my future.

[Rich82GS750TZ]

There is only one vacuum line from the the smaller of the 2 nipples on the petcock to a port on one of the carbs. Not familiar w/ your carbs. Pre '80 4-cylinder bikes had VM carbs, with the vacuum port on the rear of carb body Blogs Don't know what you got on the twins. Pics of the carbs would help. The bigger port between your 2 carbs is the fuel line to the bigger port on the petcock, Everything else is either a float bowl vent or drain. not sure. Again, pics of the carbs and the various hoses help a lot.

[Guest]

Alright, I think that solves it for me, I just wanted to make sure that only one vacuum line needed to be routed, was worried my hose routing was very messed up. I think you are correct that the other lines are just vent and drain hoses. Thank you for your help!

[rphillips]

Correct, 1 vacuum line & 1 fuel line, all others got to be either vents or overflows.