Topic: Petcock 'Sweats' A Little Fuel

[Chachi]

My petcock seems to sweat a bit of fuel. I say sweat b/c it is not actual leak/drip. Seems to be at the fuel strainer cup connection. Is there something easy to do to resolve or is it time to replace petcock assembly? This is on CB500.

[racemx51]

They make seal kits for these petcocks. Or if you dont want to spend any money just take the petcock bowl off, throw the trashed seal out and just put a good gasket maker on it.. Lightly, and carefully.. Ive done it before in a bind and it worked fine...

[Chachi]

Thanks.

[phil71]

That's bad advice. spend the friggn $25 on the petcock rebuild kit. it's cheaper than a fire extinguisher.

[Chachi]

I just noticed the 'sweat' today. I took my tank off for something else and maybe the movement was enough to start this off. What made me pay attention: when I went to shut the fuel valve off once today it shot some fuel out of the petcock. It never did it again today, but the sweating is there. Again, not much but some. I guess the sweating coupled with the one time it properly spilled fuel is enough to warrant putting a new one on.

[phil71]

the kit will come with the base gasket (between the tank and petcock), the fiber washers for the screws that hold the petcock to the tank, the screen, the 3 hole diverter gasket and the tapered o ring for the little bowl. That will stop the seeping. You also may  want to check how snug the 2 screws are on the retainer that holds the diverter (off/on/res)

[Chachi]

The screws that secure the valve lever (off/on/res) were loose and I tightened those. It didn't seem to stop the seep, but it did make the lever nice and snug. But... the fuel strainer cup has a bolt head cast on the bottom tip of it. I was able to turn that rather easily with a wrench. I turned it counter-clockwise about a half total rotation. Doing that seemed to stop the seep. Does that rotation actually tighten the fuel strainer cup to the assembly? If so how much should I tighten it?

[racemx51]

Hey Phil, Ive been running a large body shop in a dealership for years, its not bad advice if you use good gasket marker.. I dont mean like hey Im gonna go to Wal Mart and head to the automotive area. The use of a good gasket maker can be better than an actual gasket sometimes if you have any pits, marking, scratches, etc. The seals that are in these bowls are terribly cheap..

But listen to Phil..

[brooze72]

Lefty loosey, righty tighty.  There is a thin "O" ring under the bowl, be careful not to overtighten.  If your petcock is off, then you can remove the bowl without losing too much gas, to inspect the aforementioned O ring.  Best to take the tank off & do it over a suitable container IMO.  But please take Phil's advice & you'll have no worrys, mon.

[racemx51]

And SEM makes a seam sealer that works great with sealing the whole petcock to the gas tank.. Guess Im used to going the extra measure from racing Professionally... There is NO room for error.

[racemx51]

Im not trying to be a dink here guys but Ive been around for a bit... Get the seal kit.. Be gentle.

[phil71]

just a smidge more than finger tight. do not crank down on that thing

[phil71]

Racemx, i know what you mean, but most liquid gasket stuff doesn't hold up to fuel well over the long haul. sure it's fine for a race, but that is hardly valid for a street bike. Plus, race petcocks thread onto a spigot that's welded to the tank.. these flange mount (which isn't quite as good.

[Chachi]

Thanks everyone. It's not seeping at the moment, but I'll take what has occurred as a heads up to get a replacement assembly.

[racemx51]

I'll admit its hard to find a good gasket market that will last with gas. I guess Im spoiled, Ive been around a big dealership and around a different kind of bikes. Motocross works a little different.. Anyways.. I guess I should have just said, 'they make gasket kits for these things' PERIOD.. haha

[dmcgrego]

I'm having a hard time finding a seal kit for my 75 400F. Does anyone have a source? Thanks!

[phil71]

Z1 enterprises in CA