XS1100 Special gas tank petcock leaking

[MotoFo]

The tank has been off for a while. I don't remember it leaking when I took it off. But, long story short, when I have the tank upright, fuel is pouring out of the end of the left-side petcock when the lever is in the Off position - at first a lot, then a slow trickle. I replaced the rubber 'valve' piece (disc with four holes) and still the same. The right side holds tight. Any ideas as to why this is happening?

[DiverRay]

Spin the selector to the other position, prime, and see if it still does that. The selectors on each side are different, and you may have two of the same. The other thing is to polish the selector that meets the rubber selector disk. I also use a thin layer of silicon grease on the rubber/metal interface to help it work smoothly.

[Ccitis]

I gave up on mine and went with non vacuum. Been happy with that, although the on pickup must be high as when the bike is on the side stand and the fuel is lower the right side does need to be on reserve. A quirk lol.

[MotoFo]

Here is a video I took. I'm concerned that gas will leak into the carb. Not familiar with vacuum system but perhaps I needn't worry.

https://youtu.be/kODLC4dB0vY

[Ccitis]

I can't see the video, it is marked private. The point of the vacuum carb is to prevent fuel from going into the carb without the bike running. It creates a vacuum to urge the fuel downwards. With the non vacuum (old school) you do need to be mindful to turn the petcock off. The floats should close preventing carb overflow, but I don't ever trust that having dealt with a stuck float and then a crankcase full of fuel the next day.

[Radioguylogs]

The point of the vacuum carb is to prevent fuel from going into the carb without the bike running. It creates a vacuum to urge the fuel downwards. With the non vacuum (old school) you do need to be mindful to turn the petcock off. The floats should close preventing carb overflow, but I don't ever trust that having dealt with a stuck float and then a crankcase full of fuel the next day.

I think you are talking about the petcocks?

The vacuum in a vacuum petcock does not suck the fuel.

The vacuum comes from the engine intake. This vacuum actuates a diaphram plunger in the petcock. The plunger opens when the vacuum is present, allowing fuel to flow to the carburtors. When the vacuum stops, the plunger closes and prevents the gas from flowing to the carbs.

Makes sense?

Yes, you need to remember to turn off a manual petcock.

[MotoFo]

I think I fixed the video. Not too sure what to do. It's frustrating spinning gas everywhere each time I place it upright.

[DiverRay]

Special Petcocks are NOT vacuum operated. The Octy is the vacuum part. Specials are marked Left and Right, and the selector and body will interchange but are different. I would pull them off the tank, and lay them out, left on the left side, right on the right. Pull the selector off both and look for the L and R stamps, to verify someone didn't mix them up. The special also has a second nipple for a hose, for the PRIME setting. If the octy has been removed it's best to block the prime nipple.

[Ccitis]

I think you are talking about the petcocks?

The vacuum in a vacuum petcock does not suck the fuel.

The vacuum comes from the engine intake. This vacuum actuates a diaphram plunger in the petcock. The plunger opens when the vacuum is present, allowing fuel to flow to the carburtors. When the vacuum stops, the plunger closes and prevents the gas from flowing to the carbs.

Makes sense?

Yes, you need to remember to turn off a manual petcock.

Yes of course. They connect to the carb boot creating a vacuum... I just didn't spell it out like you did... obviously the petcock itself does not create the vacuum lol...