GS1150 Mikuni Carbs - ports??

[wirelessguy]

Hi folks.

I'm tyring to troubleshoot an issue I'm having and I'm just not technical enough.

I have a GS1100E and switched to a pair of 1150 carbs (long story there) Anyhow, it seems that in addition to the Fuel line and Vacuum line there is another gas line out of one of the carbs. I think Carb body #3.
Do I just leave that open?

When I try to install the tank I can't get the bike to start (using prime/normal/reserve - nothing works). However, when bottle fed directly into the fuel line with nothing attached to vacuum she does start up.
I noticed that while the bottle was filling the carb gas started to leak out of the extra port (which reminded me that it exists).

Do I need to tie that back to the fuel line as well? Does none of that have anything to do with my tank issue, etc...

thoughts/suggestions?

Thanks in advance,

[Nessism]

Sounds like a vent. There should be two. Check the carb rebuild tutorial linked in my signature to see if anything rings a bell. And post up some photos if it doesn't.

[wirelessguy]

Sounds like a vent. There should be two. Check the carb rebuild tutorial linked in my signature to see if anything rings a bell. And post up some photos if it doesn't.

You, you seem correct. Too hard for me to get good photos but there's a vent port on the back of the #1 carb and #3.

Do those just remain open or do I put hoses on them? Leave open or attached to something?

Is my tank/engine starting problem something totally separate?

Thanks.

[Nessism]

There are vent ports on #1 and #3 carb. There should be hoses attached to these. Some bikes ran these hoses to a charcoal canister and others laid the hoses on top of the airbox, open to the atmosphere. I'm not sure which is applicable to your bike. For pod filters with a Dynojet kit, Dynojet typically tells you to remove the hoses and let the carbs breathe with the port open.

[wirelessguy]

Hmmm, ok.

I do have the re-jetting and individual pods. I could run lines out just to keep dirt from getting in there since they face upward but still not clear on why my tank is so unhappy. (I've even tried attaching a different fuel sender but still no change).

[dorkburger]

I have pods and put hoses on the vents anyway. I didn’t like the idea of junk getting in them. I did have then open for years without issue however. No noticeable difference in performance.

Sounds like you you may have a few things going on. Only running on the bottle sounds like a petcock issue issue. There is a screen above it as well that could be full of junk.

Fuel overflowing from the vents may be needle / seat problems - a bit of dirt preventing them from fully closing, wear, etc.
Did you properly clean the carbs before you started the process? There are endless stories of people buying "cleaned and rebuilt” carbs that..... weren’t. Nessim’s tutorial is priceless if you haven’t.

Also, while testing with the bottle plug the petcock vacuum port by the intake on the head.

[Tom R]

Flowing out the vents is odd.... they’re so much higher than the throats of the carbs. Usually the fuel will just flow into the engine or spill out of the pods.

[wyly]

Hi folks.

I'm tyring to troubleshoot an issue I'm having and I'm just not technical enough.

I have a GS1100E and switched to a pair of 1150 carbs (long story there) Anyhow, it seems that in addition to the Fuel line and Vacuum line there is another gas line out of one of the carbs. I think Carb body #3.
Do I just leave that open?

When I try to install the tank I can't get the bike to start (using prime/normal/reserve - nothing works). However, when bottle fed directly into the fuel line with nothing attached to vacuum she does start up.
I noticed that while the bottle was filling the carb gas started to leak out of the extra port (which reminded me that it exists).

Do I need to tie that back to the fuel line as well? Does none of that have anything to do with my tank issue, etc...

thoughts/suggestions?

Thanks in advance,

I had a similar experience, I had an air leak in the vacuum line to the petcock. Fuel won't flow from the petcock if it's sucking air. Using a fuel bottle would bypass that problem.