The Marston Sunbeam Club & Register Forum

General Category => Technical Discussion Forum => Topic started by: Russ on January 11, 2023, 11:43:01 AM

Title: Fuel pipe Diameter
Post by: Russ on January 11, 2023, 11:43:01 AM
I'm sure it doesn't matter too much but I've got to curl myself a new fuel pipe which should be an interesting exercise but which pipe diameter would be best 1/4" or 5/16" I have both pipe diameters on the shelf and the relevant fittings....I'm erring towards 5/16" as it will then be the same diameter as the oil pipes lines I've made.....what size would they have been.......cheers
Title: Re: Fuel pipe Diameter
Post by: Peter 100 on January 11, 2023, 02:31:27 PM
Hi Russ
I have looked at my spares list dated 1932 and while it shows the pipes and part number it does not give the size.
My bike actual measurements are 5/16 for oil and 1/4 for fuel.
Cheers
Peter
Title: Re: Fuel pipe Diameter
Post by: Thomas on January 11, 2023, 02:41:52 PM
1/2" for oil and 1/4" for fuel at my 1937 M9. Cheers, Thomas
Title: Re: Fuel pipe Diameter
Post by: singleminded on January 11, 2023, 03:32:35 PM
5/16" for oil and 1/4" for fuel on both mine. If you have thin wall 1/4" copper it can be a challenge to stop it collapsing . Screwfix copper pipe was no good for the oil lines , it wanted to bend in my bender rather than follow the former. I used refrigeration quality pipe,thicker walled.
Title: Re: Fuel pipe Diameter
Post by: Russ on January 12, 2023, 10:52:36 AM
Quote from: Peter 100 on January 11, 2023, 02:31:27 PMHi Russ
I have looked at my spares list dated 1932 and while it shows the pipes and part number it does not give the size.
My bike actual measurements are 5/16 for oil and 1/4 for fuel.
Cheers
Peter

thanks Peter

Quote from: Thomas on January 11, 2023, 02:41:52 PM1/2" for oil and 1/4" for fuel at my 1937 M9. Cheers, Thomas

thanks Thomas

Quote from: singleminded on January 11, 2023, 03:32:35 PM5/16" for oil and 1/4" for fuel on both mine. If you have thin wall 1/4" copper it can be a challenge to stop it collapsing . Screwfix copper pipe was no good for the oil lines , it wanted to bend in my bender rather than follow the former. I used refrigeration quality pipe,thicker walled.

I use Kunifer copper brake line tube (std 22swg) 90% Copper 10% nickel.....I've also used in the past 1m straight lengths of 1/4" and 5/16" 18swg (1.2mm thick wall) from model engineering suppliers Maccmodels but it's an absolute nightmare to bend you got to get seriously physical with it even having to apply heat while in the bending tool
Title: Re: Fuel pipe Diameter
Post by: Russ on January 13, 2023, 01:02:38 PM
ok chaps so I've curled a new fuel pipe in 1/4" I'll also do one in 5/16" then I'll have both still need to fit up with final bends for connection....end fittings to be silver soldered on later......thanks everyone

20230113_124640.jpg
Title: Re: Fuel pipe Diameter
Post by: Peter 100 on January 13, 2023, 03:28:45 PM
Nice job. How did you bend it without flattening, was it just a case of pulling it around a round former?
Peter
Title: Re: Fuel pipe Diameter
Post by: Russ on January 13, 2023, 05:13:22 PM
Quote from: Peter 100 on January 13, 2023, 03:28:45 PMNice job. How did you bend it without flattening, was it just a case of pulling it around a round former?
Peter

I had to hand a 2 1/4"" x 5/16" thick x 6" long piece of pipe....it's what I used to send home my main seals on my '66 T120TT.......anyway all I did was take a length of 1/4" pipe crimp one end and filled it with normal table salt giving it lots of taps to compact the salt....that was the difficult part....LOL....then when it was full I crimped the other end off....then I bent a single 90 degree bend allowing me to clamp lightly the pipe and the former pipe in the vice....I picked a start for the coil somewhere near the middle making sure I left enough tail end to cut back for the final connections.....the trick is to be smooth and continuous in wrapping the pipe around the former.....on reflection I think 2 1/4" is a bit too big a diameter I mean it looks alright but I think 1 1/2" would be better
Title: Re: Fuel pipe Diameter
Post by: Peter 100 on January 13, 2023, 06:15:03 PM
Russ
Cheers would never have thought to do that, makes sense.
Peter