Fuel tank filler cap

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Dave Fearon
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Fuel tank filler cap

Post by Dave Fearon »

Hi new member with lots of questions and here is the first. I have a 1955 SQ4, the petrol cap has a cork washer between the cam plate and top. Should this be there as it is not shown on Draganfly diagrams, also there are 2 nuts on the vent stem one of which blocks the vent hole which doesn't make sense. Any thought on the above. Thanks Dave
will_curry
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Re: Fuel tank filler cap

Post by will_curry »

Welcome to the forum.

I've used cork successfully when the original washer made of a cardboard-like gasket
material finally disintegrated. You are correct about the nuts. They should be there to
stop the whole cap falling to bits but they shouldn't block the breather hole.

Finally, the Webmaster will probably be along soon to move this post to another
section: 'Four Stroke Technical Help'. 'Forum Help' is intended to provide assistance
on using the forum but don't worry, you're certainly not the first he's moved.
Dave Fearon
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Re: Fuel tank filler cap

Post by Dave Fearon »

Hi Will

Thanks for the info. I have ordered a rubber gasket from Draganfly. As for the nuts I understand that the second nut is there as a lock nut, but it seems unnecessary as the camplate is threaded so the secondary nut is not needed, and it definitely blocks the vent hole if fitted.
will_curry
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Re: Fuel tank filler cap

Post by will_curry »

The idea with the cap is that it is put into the tank filler hole, turned clockwise until
it goes no further and then the centre screw is tightened to secure it.

When taking the cap off first unscrew the centre screw a turn or two to free the cap,
turn it anticlockwise and lift it out.

The nuts used are thin nuts and I don't remember having any issues with the vent being
blocked but I'll have a look tomorrow . . .
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Re: Fuel tank filler cap

Post by admin »

Duly moved!
(I think moderators can move things as well, in truth....)

SG
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Re: Fuel tank filler cap

Post by Simon.Gardiner »

will_curry wrote: Sun Nov 20, 2022 10:00 pm The idea with the cap is that it is put into the tank filler hole, turned clockwise until
it goes no further and then the centre screw is tightened to secure it.
As with Will I use the centre screw to finally tighten down the petrol cap (it the petrol cap loosens while you're riding you'll get scared silly by something suddenly making one heck of a racket).

The two locknuts go together somewhere further down the centre screw thread, there's always quite a bit of room for them on the petrol caps I've got.

SG
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Re: Fuel tank filler cap

Post by nevhunter »

I've had vent holes blocked and numerous loose caps. The two thin nuts should be a distance down and just lock each other in the correct position, which should NOT block the vent hole. I've had the vent block because something blocked it.(Muck). Clean it with a small drill About 1/32. Good quality and thick gasket material works ok and make the OD big enough to tuck in the fold of the cap that forms the Knurl. Nev
Dave Fearon
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Re: Fuel tank filler cap

Post by Dave Fearon »

Thanks for the replies I now understand how the filler cap locks but the nuts do cover the breather hole if locked in any position as you can see from the image
IMG_20221121_112717552_HDR.jpg
will_curry
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Re: Fuel tank filler cap

Post by will_curry »

The vent hole as I remember it is on one side only, much smaller and almost
under the head of the screw, Nothing like what you have.

Later on I'll look out a filler cap and take some photos.
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Re: Fuel tank filler cap

Post by volker.halbach »

Will is right. On my cap the vent hole is between the chrome cap and cam plate on one side only. You could drill a small hole there. If the hole is above the cam plate, I would also expect that petrol is less likely to leak through the vent hole.
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