petcock not functioning correctly

[Guest]

I replaced the old pet cock on my '77 gs750 with a new one. In the on position it still lets a little fuel by, flooding all 4 carbs. Should I scrap it and get another petcock or is there something I should do to try and resolve the problem in this petcock.
I've verified it is an OEM petcock...with the tank off the bike the petcock still leaks in the on/reserve positions.
The carbs were cleaned and had new orings and gaskets put in this winter by one of the members here.
Fuel doesn't come out of the overflow drain in the bottom of the float bowl, its overflowing around the top of the float bowls. All the screws are snug and they have new gaskets.

[GSXR7ED]

How's the vacuum hose lookin'? What I mean is, does it have a proper seal? (If you don't know...it's the hose going from the petcock to chamber #2 carb)

My vacuum hose had a 1/8 inch slit at the tip and it caused a leak into the primary airbox.

Ed

[bigskybldr]

I have replaced all the hoses with new ones, they all fit tight and have spring clamps on them. Even now with the tank off it still drips fuel. The service manual for my bike says to hook up the vac line to the #3 carb(VM carbs)
thanks for your response Ed

[BIG_brother]

Aftermarket?

[GSXR7ED]

No problem...there's been several threads about petcocks and by process of elimination, it seems as though you'll have to check your carbs.


Ed

[bigskybldr]

I'm not positive, but pretty sure it was a Suzuki petcock.

[tom203]

I'm not positive, but pretty sure it was a Suzuki petcock.

first you said "I've verified it is an OEM petcock...with the tank off the bike the petcock still leaks in the on/reserve positions"

Whatever, your petcock is no good- should not leak in on or res spot with bike off. If new, might be defective manufacturing. Don't fight it,just get another .

[bigskybldr]

thanks Tom. after I answered Big Brother's question about if it was an aftermarket part I found the slip that said it was OEM and edited my original post saying it was verified OEM.

[barnbiketom]

also, even if the petcock DOES leak while bike is not running, the CARBS should not leak gas..

you have two problems.

[Shwartz]

Any chance the petcock just needs to be flushed? the rubber seal in it can't seal properly if there's junk in it. I'd pull it off the bike and put the air compressor on it first. See if you can dislodge anything. Maybe even pull it apart and check. After all of that you'll probably still need a new petcock if it won't stop leaking.
If it's new, can't you return it?

[bigskybldr]

I wouldn't think anything got by the petcocks filter but maybe there's something in there from the factory. I'll pull it off this weekend and give that a try, I hate to pitch a brand new part.