petrol tank cap washer

[volker.halbach]

What kind of material can I use to make a new washer for the petrol tank cap that doesn't shrink?

So far I have used a washer cut from cork. This works well except that the cork dries out over the winter when I store the bike with an empty tank. Every spring I find myself cutting a new washer. I ordered a plastic washer from Draganfly, but its outer diameter is slightly too small, so it falls out of the cap, when the cap is removed. Any idea what I could use to make a new washer?

[Roger Gwynn]

I assume that you are talking about the large filler cap 1930-55 type. I have been slightly annoyed by the washer falling out but never enough to do anything about it. I will have a word with Draganfly to see if they can alter it. The best material to cope with modern fuels is Neoprene or Viton.

[adrie.degraaff]

You also need to use the right cork out of one peace not the glued particles ones, they can be bought from a hobo- clarinet repairshop or the big internet Chinees, they about 3 ponds a leaf for one bigg cap and a few smaller.

[Roger Gwynn]

I have spoken to Draganfly and they say it will not be a problem to increase the OD, so I have drawn it up and sent it in, the next batch will be a better size. The problem is if it is too big the gasket will tend to ruck up or wrinkle, hopefully I have it right with an increase of .05".

[volker.halbach]

Thanks, Roger. Yes,it's for the large 1930-55 type. It looks like an increase of 0.1" might be needed; but I haven't tried whether that's too large. Trimming down a washer isn't a problem, of course.

[tonyh]

I think Nitrile rubber is fuel and oil proof.

[JohnnyBeckett]

hi i spray the cork in my petrol cap with WD40 to stop it drying out in the winter or when i am standing my motorcycles up for awhile

[nevhunter]

I use thick cardboard proper gasket material and make it a large enough diameter to fit tightly into the corner of the cap. It takes a bit of fiddling to get it in. Bit like the reverse of putting a tire on a rim, but never had one of them fail (or Leak). Nev

[charles.bulloch]

An MZ cap washer for a TS250 fits straight in.

[volker.halbach]

Thanks to all. I thought about making a washer from thick gasket paper, but thought that paper gaskets are not a good idea for surface moving relative to each other. I'll cut a washer from a Viton. I am not keen on the ritual of boiling or soaking cork and got already rid of the cork in the fuel taps.