leaky fuel petcock

[pirateman54]

as all who own an old dream know the only thing worse than the throttle design is the fuel petcock. As this is my first restoration of an old ca 160 dream I was like many reassembling the tank to make that first start. 2 A.M. tanks clean and rust treated pour in the gas and whoa. So bought the rebuild kit. I read here horror stories about rebuilding the valve and it still leaking. I just rebuilt mine and so far its holding. A couple o things I noticed. 1 cork gasket is thicker than what was in there prolly cause its new. 2 new rubber plug with metal and rubber tube doesnt work on a 160. Have to trim them off flush with the surface. dont trim the alingnment thingy on the edge in between em. you need that. My kit did not come with washers for the mount screws reused the old ones. I soaked the whole kit in fuel for an hour before assembly. Old aircraft mech. trick. Also I put a thin coat of form a gasket on the tank mounting surface I mean thin and the washers for the screws. Sorry i didnt snug the screws i cranked em down and waited. then i cranked em a tad more. as the cork compresses to seal the selector i figured that may be why some guys have selectors leaking right away. I leaned about the bennys of a little sealant form working on my harley. rubber gaskets on old bent up warped, rusted bike leak. A little rtv on oil gaskets or permatex on fuel may help keep things where they should be.also be careful with the bowl gasket. make sure you tuck the thing into the flange carefully so it seats. light push with a common screw driver blade to seat it. Any way that worked for me. thanks

[Snakeoil]

I just went thru the pain of leaking cork seal on a BSA. I ended up having to machine new seals out of an old wine cork. I was not aware that we had Hondas out there with cork seals. So, with that in mind, here's a couple more tips regarding cork seals.

You don't want to let them dry out if you can avoid it. That means don't drain your tank and leave it that way. They will dry out in a few weeks and no longer work. If you have to drain your tank, I would suggest removing the petcocks and putting them in a sealed container of gasoline to keep the corks moist and swelled.

If they are dried out, but still in decent shape, you can put the cork seals in boiling water and they will come back to life. I've also had luck soaking them overnight in gasoline as Pirateman suggested here.

New cork seals should be about 30% thicker, larger, whatever the correct adjective applies, than the mating part they will seal to. As an example, the bore on my BSA petcocks is roughly 3/8" and the recommended size for new seals is 12mm.

Depending on how they fit into the petcock, some liquid soap helps ease them into position and also lubricates them without sealing them. The cork wants to absorb liquid, just like a wine bottle cork does to stay swelled and sealed. So, using grease or similar could seal the cork. I have seen some say to use plumber's grease. But I prefer liquid soap.

To make your own cork seals, a Dremel is a handy tool. The cork seals in Ewarts fuel taps on BSAs and other Brit marques are barrel shaped so I spun the cork in a lathe and cut the OD with sanding drum mounted in my Dremel. Holes are best bored at very high RPM using something like a burr with mutiple cutting surfaces versus a drill bit which will chew thru the cork. You can open up a hole with a small mounted stone of the correct diameter in a Dremel. I also found that for bringing a piece to a final dimension a fine cut file or sandpaper works, as long at the cork is spinning at high speed. You need the speed for the teeth on the file to shear the cork. File will plug up so you have to clean is regularly.

Hope this helps. If done right cork seals work very well and I'm not sure anyone has come up with a man made material with the same properties to seal the designs that use these seals. There have been attempts, and they are still being sold. But they don't work.

regards,
Rob