Ball bearing in vacuum petcock?

Hey guys. Was rebuilding my petcock of my '81 KZ1000 M1 yesterday and noticed what looks like a ball bearing in the bottom (where green arrow is pointing). Is this indeed a ball bearing? If so, should it move (spin, lift, etc.)? This one is frozen. I'm thinking its supposed to move to provide intake for the vacuum and since its stuck its causing the leaking. Thanks for any help.

petcock_sm by AlexP524 , on Flickr

Alex

I have not seen everything, but I'm sure I've never seen a ball bearing in a fuel petcock before.

Are you sure you are not looking at an aluminum plug in the bottom of thee the petcock?

All the petcocks have that.Dont believe it is a ball bearing,and dont believe it is supposed to move-otherwise immediate fuel leak.It may be a plug of some sort,however.If u r rebuilding yours,I assume u dont need my spare one?bj

It's probably a brass bead, they use them to seal the unneeded passages that come as a result of machining the part. You can find several of them on carbs. The vacuum system should be completely sealed as any source of air would reduce the amount of vacuum and cause many tuning issues.

How exactly is you're petcock leaking? Is it allowing fuel to go through without vacuum? Is there gas leaking around the petcock? Is there gas getting into the vacuum line?

Sounds likes what JakeB said. Here's a better pic.

It was leaking before and I bought a rebuild kit. I took it apart, cleaned it, added the new parts and put it back together. I'm not sure exactly where it was leaking from before, but now it leaks right out the side of the square plate in back where the sqare rubber vacuum valve (?) is.

Here's a vid of the leak.
flic.kr/p/8J2STS

Thanks guys!

The square plate "back there" has two very thin rubber gaskets
with a small check valve in the middle.Is that what u replaced?That is the mechanism that pulls a vacuum when engine is running to allow fuel to flow.If it is leaking without the engine running either parts are defective or u didnt assemble properly.Good luck.bj

You can see in your video it's leaking from the diagphram, just look to the top left, just below where it says Fuel.. heh Coming out from right at the top screw. Possibly more areas I can't see in the vid.

Dang that's some leak. I'm having issues with my vac petcock too, letting gas through even with no vacuum, i.e. when the bike is off and no matter what setting it's on between pri-on-res. wasn't sure if a rebuild kit would do the trick, now this video all scares me away from that idea. . . probably just going to replace it once I find the right one. . .

Thanks for the input guys.

The engine was off. Just turned the lever from ON to PRI and, as you saw in the vid, it starts squirting out the side. I'll have to take it apart and re-do it to see if I assembled the pieces wrong or maybe the rubber gaskets got wrinkled, or something equally stupid, when I put it back together.

@hocbj23: Definitely still want your spare petcock.

@Nunzi: Nothing wrong with the rebuild kit, more likely the rebuilder (me!). :blush: Don't go by my experience. I'm sure I just messed up a simple re-build do to lack of experience.

When you take it apart look over the housing really well for any cracks or any gouges in the mating surfaces.

Here is a diagram of the petcock.