Petrol Tank Cap

[Cider1]

Hi
Can anyone tell me how to dismantle the petrol tank cap.  I want to replace the cork washer and can't figure out how the cap separates. By the way, it's a standard 21/2 inch one with what looks like a split pin in the middle.
Thanks
Frank

[RichardL]

Frank,

Is that a winged knob half-turn top with a flange that captures two pins in the neck. If so, the swedged-on handle does not deal well with manual removal and replacement. I cut a rubber gasket about 2mm thick that fit over the flange. Then, I fit a fat o-ring between flange and gasket to keep the gasket laying flat.

Hope this helps and is even applicable.

Richard L.

[Cider1]

Hi Richard
Thanks for the reply, but my cap is the more modern 'standard' one.  I've enclose a couple of pics of it.  It doesn't look as if it should be that difficult to strip but I don't want to force it and end up making it unusable.  I would appreciate any advice on how to proceed.

Thanks
Frank

[RichardL]

Frank,

I can't wait to hear what the real answer is from someone who actually knows, but, for laughs, allow me to play "Guess the Widget." (A TV show I just now made up.)

I'm thinking there must have been a reason for it being a split pin and that it might not have been intended for disassembly. So, what's going on on the other side of the hold-down cone? My guess: there's a boss with a hole in it brazed to the back-side of the cap such that the hole is sized for a press-fit of the pin. The pin, being split, gives a bit when hammer-driven into the hole, but holds nicely. Judicious use of the hammer allows the cone to stay a bit off the gasket so that the gasket can have a bit of freedom. If this guess is correct a strong pull on the pin could remove it and/or, maybe, dish the topside of the cap.

As I said, I can't wait to hear how wrong or, much less likely, right I am.

Richard L.

[LJ.]

My petrol cap centre piece is slightly different. I think this was intended for a chain to stop cap from getting lost, possibly the caps were made for other vehicles and or containers. There is no need to remove the centre piece as there is nothing under there other than a spring, removal is not too difficult if my mind serves properly. The cork gasket seal can be removed easily with a sharp modeling knife. I take mine out and boil it in water and put it back in the other way round. Failing a cheap restore they are readily available from the dealers.
 

[a101960]

From day one the cap on my RGS has always been incontinent. I recently had to replace the seal. The original one was rubber of some kind and with the introduction of ethanol to petrol it very soon started to rot. I have replaced it with cork, but it is till incontinent.

[Brian]

Its dead easy. Grab a pair of pliers and squeeze the end of the split pin together and it will all fall apart. There is a spring under there as well. Once you have had it chromed or put in a new seal or whatever just reassemble it and spread the pin eye again and its done.

[Cider1]

Hi Brian
Thanks for the guidance, it worked a treat.  I've just got back from a 50 mile test ride and for the first time the tank is clean without the usual petrol streaks.

Frank 

[RichardL]

Frank,

To satisfy my curiosity, how was the pin held to the cap?

Richard L.

[69Bonni]

Hi Guys

On a slighly different note... The butterfly knob type AKA RGS, Goldie etc have been getting on my wick! i have one on my A65T which is .... Ok ish. The one on the Goldie tank is driving me mental. I think its a Patten type which makes it worse. I have thinning hair and this is making it thinner.

I very nearly rammed a BL88dy great cork in the hole and belted it with a mallet!

Having calmed down, i did wonder why id seen bikes running around with a womans elasticated hairband over the tank filler(you know the sort of thing you see in girls hair when they have pigtails to tie there hair back) Well its there obviously to catch the slops as petrol tops the tank! Good Idea!

But looking at the (poxy) mechanism, is that really spose to grip the inside of the tank neck and hold the cap down?? Well there must be a better way!
An idea came to me the other week (in fact a couple of ideas). The first was when i was helping someone with a caravan and on the front locker box door was a lock that might be adapted to a cap, It consisted of a threaded barrel with an essentric locking cam at one end and appears to be sprung loaded, the "Key" turns a threaded rod screwing into the barrel, this draws up and turns the barrel against the spring tension. The drag of the turning action moves the essentric cam to a stop "the Locking position" (where the cam has now moved inside the frame but its not tightened down). Continuing to turn the key screws the barrel up the threaded rod and starts to pulling the lid up tight. I think they call it a compression lock.

I'm thinking if you can modify the cap with a threaded barrel and a cam on the end, it could cam under the rim of the filler (down inside the tank) and tighten up on that pulling the cap shut.

Clear as mud eh! I'm starting on a prototype so i'll post the idea then,

The other idea was when i saw a Pipe stopper in a Plumbing store, see attached picture and that speaks for itself

Anyone else cured this problem?

Steve