How to bench test a petcock?

[Ricko19]

Can someone please tell me how to benchtest a petcock? I tried to find it in the search function, but nothing specifically about that.

I have a 1980 GS/X750ET with original fuel tap. It doesn't have a handle but a recessed slot for a screwdriver to change the tap setting. It only has 2 postions - slot horizontal = normal operating, and Prime which is at about 10 o'clock. It has a fuel line connection and vacuum pipe connection.

It was set on prime when I bought it and has been ever since - the previous owner mentioned some problem with it but I can't remember. The tank is now out an on the bench. I turned it back to normal position then back to prime but nothing is coming out???? Shouldn't it start flowing on Prime?

Also, the slot 'tap' will spin all the way around as many times as you want to - not just limited to the 2 positons its supposed to be - does this mean its had it?

Can someone please tell me how to test the fuel tap while its on the bench attached to the tank?

Thanks

[SqDancerLynn1]

Just replace it, that is one of the worst petcocks www.z1enterprises.com carries a line of replacements around $45 Or you can go OEM for around $75.
It should flow on prime, but I think you have to apply vacuum to get it started on prime

[rphillips]

Like he said, Orig. is fine with me, as long as it isn't an orig. "80" model with the little slot. Just my opinion

[Larry D]

Agreed, the '80 petcock is the worst. Get a replacement. When you do, make sure it will bolt up properly and have enough clearance when the tank is back on the bike.
You can do a search through the forums and see what other members have done with the dreaded '80 petcock.

[twr1776]

Unbolt from tank, throw in garbage. Buy new OEM one, good for next 25 years. Seriously although they are not cheap IMHO you are better off getting a new one and forgetting about it.

[Ricko19]

Thanks guys, will research a replacement one. I prefer OEM myself, but if my standard one is crap, will any other model OEM ones bolt straight onto my tank?

I saw a few comments on the dreaded 80 petcock when I was going throught the search feature, but didn't realise they were refering to MY petcock!! I thought they were talking about a different non vacuum model on some of the touring models.

I'd prefer not to go aftermarket for issues of reliability, so do any other OEM's bolt straight up?

cheers

[Dogma]

IIRC, the bolt spacing on these is also different. I have the replacement part from Z1 Enterprises. It didn't Say Suzuki on the box, but it looks exactly like it, and has been functioning perfectly for the last couple years.

For future reference, Lynn is correct: you have to apply vacuum, even on prime. The difference is, on prime, you apply vacuum once and it keeps flowing. On run, you have to keep applying vacuum.

[Ricko19]

Thanks Dogma, I understand now I had a look on Z1 for my model, but when it bought up the petcocks that were supposedly for my model, (ET) my model wasn't in the list for the models it suits (on the right of the petcock picture)??

So its either these or OEM. Will check for both. Cheers