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Fuel tank breather?
Northy - 28/2/04 at 12:49 PM

What do people do with the breather pipe from the fuel tank? Does it need a one way valve? Or just a pipe to let it breath to air?

Cheers


theconrodkid - 28/2/04 at 12:55 PM

best to have a one way valve,my tank used to empty over a week in the summer with evaperation


jonti - 28/2/04 at 01:58 PM

Don't you need a two way valve to allow for expansion on a hot day ?


Surrey Dave - 28/2/04 at 01:59 PM

Isn't a 2 way valve , just an open breather pipe?


theconrodkid - 28/2/04 at 02:39 PM

hold on dave ill get my calculater out


CairB - 28/2/04 at 05:45 PM

Northy,

I used the valve off the Sierra filler assembly. A vent pipe was connected to the top of the fuel tank then up in a loop as high as possible then down to the Sierra valve then to atmosphere. From memory, I think that the valve would shut off when upside down but otherwise give free breathing both ways.

I haven't noticed any problems...but I haven't tested it by rolling the car.

Surrey Dave,

[Quote]
Isn't a 2 way valve , just an open breather pipe?
[Quote]

Not necessarily. It could be implemented using 2 check valves in parallel facing opposite ways. This would mean that it would seal in both directions unless the cracking pressure was exceeded in either direction.

Cheers,

Colin


Northy - 29/2/04 at 08:53 AM

Now I'm really confused

Is there any requirement for SVA?


Surrey Dave - 2/3/04 at 10:02 PM

You what!!


Northy - 2/3/04 at 10:07 PM

Dave I was just about to reply to this thread!

I phoned Beverly to ask the SVA guy there, and he says he's not bothered at all. Wouldn't even be checked.

So, am I best off fitting a one way valve to avoid evaperation? If so where can I get a Locost one? I'm not prepared to pay Demon Twats prices


wicket - 2/3/04 at 10:26 PM

Graham

Here's another source
http://www.bsr-aerotek.com/fuel18.htm

Eric


Jon Ison - 2/3/04 at 10:28 PM

valve out of a push bike, cheap as chips.


Northy - 2/3/04 at 10:35 PM

Push bike? Are you serious? What valve?


JoelP - 2/3/04 at 10:42 PM

inner tube one i guess. makes sense actually!


Northy - 2/3/04 at 10:57 PM

quote:
Originally posted by JoelP
makes sense actually!


Not to me!

Can you explain how you'd use it?


Jon Ison - 2/3/04 at 10:59 PM

yup inner tube valve, works just fine, even sufficient to get by scrutineering for off road events...........


Northy - 2/3/04 at 11:02 PM

Which way round would you fit it? Sorry if I'm being thick, just not understanding how it would work!


Jon Ison - 2/3/04 at 11:13 PM

to allow air into tank but nothing out, they are a very simple 1 way valve which is what your looking for, have a flexible tube from your tank breather with the valve in the end of it...........


greggors84 - 2/3/04 at 11:17 PM

Would you use the thread on the bicycle valve or just attach it another way?


Surrey Dave - 2/3/04 at 11:41 PM

I like it 'Locost' and simple , just push it into some flexible pipe and crimp or use jubilee clip.

Will the vacuum in the tank be enough to open the valve?

If I grind to a halt with fuel starvation I'll no who to blame , Mr Ison

All the local motorcyclists will be please that i'm not dropping fuel at roundabouts then!


Mark Allanson - 2/3/04 at 11:41 PM

I would have thought that cutting out the valve from the inner tube and fitting it into some 8MM ID Petrol suitable rubber pipe, other end fitted to the tank or filler neck


madforfishing - 2/3/04 at 11:50 PM

You're too fast Mark.
That's exactly what I have done about 2 nights ago.
I thought I was being SooooooooooooO
clever.
Damn, you guys are good. (or eves-dropping)
I'll never conquer the world at this rate.

Off Topic: ref evesdropping etc...
Do you think Claire Short signed the Official Secrets Act in her capacities as a MP ?
If so why isn't she banged up in HMP Holloway ? ( or the Tower) ?


greggors84 - 3/3/04 at 02:43 AM

She probably knows alot more, that she would tell if they banged her up!


JoelP - 3/3/04 at 09:38 AM

anyway, would you want to bang her up in the tower?!?!?!?

but yeah, she knows more, should probably be silenced anyway. she's SO naive...


jonti - 5/3/04 at 06:29 PM

quote:
Originally posted by Surrey Dave
Isn't a 2 way valve , just an open breather pipe?


Think this has been covered above but my ten pennoth for what it's worth
On the face of it yes but not if both "ways" have a spring loaded valve. Air can be pushed and sucked through but liquid not under pressure ie fuel slop will not pass. You do need two pipes for this to work though.

However, from what's been said the pressurisation of the tank is not an issue so as long as air can get in and fuel can't get out it's seems like you're ok.

Bike vave is a good idea.. I like that





[Edited on 5/3/04 by jonti]


Jon Ison - 5/3/04 at 06:42 PM

bike valve = locost.
they do work fine too, just as good as a £XX version.....

Bit like the USA inventing that pen that would write in space/zero gravity and spending millions$$ on it,

wot did the Russians do? took a locost pencil


Dale - 5/3/04 at 07:32 PM

Could you not put two of these valves in. One in each direction as to allow excess pressure out and one to vent in. Being in Canada I am wondering if your talking about standard automotive style valve (that is used in most bicycles here or the euro valve that is only used in more expesive bikes here. (the kind with the operational parts external to the case)
Dale


jonti - 5/3/04 at 07:47 PM

I would have thought two pipes with a valve in each.....one in one out would be ok and that's what I had intended.

Guys on here seem to indicate that , in practice, positive pressure in the tank is not a problem though.... Mind you , on a hot day with a nearly empty tank I would have thought the build up could be significant.
As another afterthought for Jon.....How does the rubber in these bike valves fair with long term exposure to petrol ?