Replacement petcock

[Upright]

Would this work on my '79 XS11F?

Replacement petcock from Partsnmore

[sidecarKev]

Yes and no. You would also need the adapter plate sold below it.
This one would work also.

MikesXS
Part #20-0019

[Upright]

What would I do with the vacuum lines if I use the Mike's XS petcock? Just cap them off, or would that upset the delicate balance of vacuum?

[sidecarKev]

Yep you would have to cap them off. No problem with that. Your most cost effective route would be to get one from partsnmore and run all 4 carbs off one petcock. Take a petcock you have now and fill it full of epoxy or something and just use it to plug on side.

Are your petcocks really bad? Both mine leaked terribly. I used the petcock rebuild kits and haven't had a problem since.

[Upright]

I had a lot of work done over the summer to get it running, including a complete overhaul of the carbs and the petcocks were rebuilt at the same time. Now, one is leaking. If this is going to be a constant problem, I thought I'd just do away with the current system and install some petcocks that can actually be shut off.

Thoughts?

[sidecarKev]

go for it. cant hurt anything. I'm sure lots of people have.

[rover]

The only drawback is that you will have to turn them off when you park the bike. The originals turn themselves off when the vacuum goes to zero. If you park on the side stand, the lean angle can allow the float valves to open, causing fuel to keep oozing into the carbs. I took the octopus off my special, and usually forget to close the petcocks. Did a lot of premature oil changes. My standard has the same vacuum petcocks as you have, I rebuilt mine, and they are fine. Now I am rebuilding the octopus for the special.

[nashville_bill]

Be sure and check the vacuum shut off valve after you rebuild it. The replacement diaphragms I have found won't completly shut off the fuel. The part that sticks out and has the o-ring isn't long enough to stop the gas. On the other hand, let me know if you find a part that works for your rebuild so I can put the octopus back on my Special. I don't like having to turn off the gas. I'm old and don't always remember.