1980 XJ650 petcock pissing gas out the vacuum port

I recently purchased an XJ650 and rebuild the petcock, with all new rubber parts, along with the rest of the bike. When I went to run it, I found that cylinder 3's exhaust was cold, and it turns out that there's a ton of gas going out the vacuum line. I disassembled and reassembled it and the problem persists. As a quick fix I capped both the cylinder 3 port and the petcock port and just set it to prime when its running, which works, but I'd like the vacuum shutoff to work. Is there something I'm missing when I rebuild it? Are there any aftermarket petcocks that are worth the money/will fit an XJ650G?

 

You may not have the diaphragm in the petcock in right ,or it is not seated right.

 

Did you read this rebuild thread?

https://xjbikes.com/forums/threads/rebuilding-the-yamaha-vacuum-fuel-valve-w-pics.25058/