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Discussion Starter #1
Picked up an 82 CX500C a month or so ago and been having some issues. Pulled the carbs apart to clean them, and pulled the petcock as well. Diaphragm on the petcock was bad, so I did a rebuild kit on it. Got everything back together today and I'm not getting any fuel from the petcock.

I have it on RES, and I have the right side port connected to the right side carb. Cranking it over and nothing.

I tried removing the tank and sucking/blowing on the right side port tube to see if I could get some movement, still nothing.

I connected a line to the outside/left port (which originally wasn't connected to anything at all) and when I sucked/blew on that line, I got a little trickle of gas, and then it stopped.

Is it possible I put the petcock diaphragm together wrong? The only discrepancy I could notice while using the Haynes manual is that I maybe have put the large diaphragm in backwards. But really not too sure. There's a little metal piece between the diaphragms that the nipple of the diaphragms pop into (with some help of a screwdriver). I attached both of those. But then there's also a nipple on the other side of the large diaphragm that pops into the spring retainer piece. Maybe I have those backwards? I have the smaller nipple in the spring retainer piece, and the larger one in the metal piece on the other side that connects the two diaphragms.

Any ideas??
 

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Discussion Starter #2
UPDATE

I've fed fuel directly into the carbs from the T carb inlet tube and the bike fires up immediately. But still no draw from the tank. Gotta be a petcock issue, but I can't figure out what it is...
 

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I would recommend buying a cheap aftermarket non vacuum petcock. I did and have never looked back and regretted it. It eliminates future problems on the road too. When you removed the petcock to rebuild it, did you get the filter screen out of the tank and clean it too? Sometimes they get stuck in there and newbies don’t realize it’s there.
 

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Discussion Starter #5
I'll definitely get a new petcock, but the OCD in me still wants to figure out why this one isn't working. Brand new diaphragm and all, and still nothing. When I suck on the vacuum tube with the petcock on, fuel doesn't flow.
 

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Make sure the vacuum line is connected to the correct port on the petcock, or open the vacuum chamber onthe petcock and put the spring on the side of the diaphragm on the back side (not the vacuum side) of the diaphragm and now you have a non-vacuum petcock.
 
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