1/4" Diameter Oil Pipe BSP Fittings - For Douglas 2 3/4 hp Models and other Flat Tank Motorcycles

Product no.: 0891 DG234_1/4Pipes

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from £5.00
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This listing shows the various pipe fittings we can supply to fit the 1/4" outer diameter oil and petrol pipe fittings as used on the Douglas 2 3/4hp models (and other early Edwardian machines).  Most of the nuts are CNC manufactured in stainless steel, and the ferrules in brass.  

As background to this listing, when restoring my own 1919/20 Douglas 2 3/4hp model (as shown in photographs), I found that the pipe fittings, as fitted to the original hand pump and drip feed oiler to the engine were mostly unavailable commercially.  Therefore after conferring with other owners on the Douglas forum - to confirm the original oil pipe diameter was 1/4" outside diameter, we have manufactured the various fittings and pipes to make up a full oil feed assembly, as well as the engine drain breather pipe.

The parts listed below can all be ordered individually from this listing (select the sub item to order), or as a full assembly (at a similar price to buying individually, but we have pre-formed and soldered pipes/ferrules to our templates on our own pipe bending jig). 

Note:  As I write this update (Aug 2020), pipes are supplied in base copper unplated.  I will look to be having some plated in a bright nickel finish shortly - email for update on sales@racingvincent.co.uk.  Likewise, I will also be adding petrol pipe assemblies shortly - but these may only be relevent to the Douglas Amac carb fitted to my own model - again, email if more details required.

The parts we can supply are as follows (prices are for 'each' unless otherwise stated):

Douglas 2 3/4hp/Pre-1930 Oil Pipe Fittings : 1/4" Bore Pipe

Reference No Item  Description Parts Included
0891_1 Nut and Ferrule To Fit Engine One Way Valve 1/8" BSP thread nut (CNC from Stainless Steel to original 0.5" AF Hex profile - hex milled from solid bar)  and tapered ferrule to fit 0.5" pipe.  These are the correct thread for the One Way Valve fitted on Douglas 2 3/4 hp crankcases, that the oil feed pipe attaches to SS Nut and Brass Ferrule
0891_2 Nut and Ferrule To Fit Drip Feed Oiler Union 7/16" x 20 tpi thread nut (CNC from Stainless Steel to original 0.5" AF Hex profile - hex milled from solid bar)  and tapered ferrule to fit 0.5" pipe.  These are the correct thread for the oil pipe unions at the base of the Oil Drip Feed Regulator fitted to Douglas motorcycles from @1917 - late 1920's (as well as many other motorcycles of that era).  See photographs to show this drip feed unit, which feeds through the flat tank, with the unions under the base of the tank - two required per Drip Feed Unit. SS Nut and Brass Ferrule
0891_3 Nut and Ferrule To Fit Bottom of Handpump

1/4" BSP nut (good quality commercially available type - bright nickel plated steel) and brass 'flat faced' 1/4" bore ferrule, of the correct type to fit the bottom of the handpump of Douglas models from (approx) 1917 - late 1920's.  

Note:  if you have a Douglas or flat tank model with a similar type of handpump, please check the base of the handpump union before ordering this item.   My original Douglas handpump has a bottom union with a flat face - these brass unions have been specifically made to fit that type of bottom union.  If you are intending to use a 1/4" bore oil/petrol pipe with 1/4"BSP thread, check this first - if the union it is to abut to has a conical face (as most later petrol and oil pipe fittings were) - then we also manufacture a similar item with conical face ferrule - which it Item 0191_4 

Bright Nickel Plated Nut and brass Ferrule
0891_4 Nut and Ferrule to fit tapered end petrol taps with 1/4 BSP Thread 1/4" BSP nut (good quality commercially available type - bright nickel plated steel) and brass 'Conical' 1/4" bore ferrule, of the type commonly fitted to petrol taps with 1/4" BSP threads, but to fit 1/4" bore copper (fuel) pipe Bright Nickel Plated Nut and brass Ferrule
0891_5 Complete Douglas 2 3/4hp Engine Feed Pipe Set 1919-25

As per the accompanying photographs, this set consists of all the components required to make the 1/4" bore oil feed pipe set from handpump, through drip feed, to engine one way valve.  

It consists of the following components:

A. 1/4" BSP nut and flat face ferrule (Item 08913) - note this is soldered to the copper pipe on this end, but if you wish to get the copper pipes plated, they can be unsoldered on one end, as the nuts are already plated.  The nuts can then be added after plating, and the ferrule re-soldered on

B. Short curved 1/4" bore copper pipe, with drip feed oiler unit brass ferrule soldered to it and 7/16" x 20 tpi ferrule nut (i.e. Item 0892).  The copper pipe is formed to shape to fit the standard Douglas 2 3/4hp 1919-24 petrol tank and drip feed unit as per photographs.  Most Douglas models of same period used similar tank/drip feed unit - but it may be necessary to give the copper pipe a slight tweak if your model is positioned slightly differently,  Note: we now supply a second spare piece of copper pipe - in case the pipe supplied does not fit your particular model - and you decide it is easier to just bend a pipe afresh - in which case just unsolder the ferrules, and solder them to the spare pipe after bending to shape

C. a second drip feed nut and brass ferrule (Item 0892), soldered to a copper pipe which has the correct curved shape for the output feed pipe as shown in photos

D. 1/8" BSP nut and brass ferrule (Item 0891_1) soldered to a copper pipe which has the correct curved shape for the corresponding input feed to the engine one way valve.  Note, we make this pipe and item

E above approximately 0.5" overlength to allow for a small amount of 'tweaking' in case your model is slightly different.  You may want to shorten them to allow approx 0.5" gap between both pipes where the rubber anti-vibration distance piece fits.

F. Rubber distance piece/anti-vibration piece + ferrules (Item 0891_8)

As per photo - the pipes have been formed on a pipe bender to the templates I have created for my  own 2 3/4hp model, but if your model is slightly different, the copper pipes can easily be tweaked before plating.  copper pipes are deburred and tinned before soldering nipples, but can easily be removed and re-fitted with use of a propane blowtorch and plumbers solder (not electrical solder),  The two main pipes to the engine are supplied oversize  and can be final cut to the customers own bike (and these may also be suitable for other models - i.e. the 4hp model of the same period

4 nut and ferrule units, 3 copper pipes and rubber distance piece + Spare Copper pipe
0891_6 1/4" bore copper pipe set

This item consists of 4 lengths of 1/4" outside diameter, 20 SWG gauge copper pipe (UK manufactured), which are of lengths that will allow you to bend the oil pipe feed set (Item 891_5) and engine drain/breather pipe (0891_7) yourself.  You may find this useful if you feel your pipes may be different to the pre-bent pipes we offer, or you just want to bend them youselve.  We have made each length fractionally longer than it needs to be (and I find using a slitting disc in a small angle grinder much easier than a hacksaw for cutting to length).

The 4 pipes are of following lengths:

1 x 120mm length (pipe between hand pump and drip feed unit - I have found this requires a compound curve to fit neatly)

2 x 160mm lengths - the oil pipes between drip feed unit and engine one-way valve

1 x 200mm length.  Engine drain/breather pipe (note:  I think this pipe may vary by sub-model, dependent on which footrests/gearbox/ base pan is fitted to your model.  I also cut the end of the pipe at 45 degrees, which I think looks nicer)

Each pipe is linished at its end and deburred externally and internally

We may also be able to offer custom lengths of pipe (pro rata by length) if we have enough in stock - email for a quote.

0891_7 Engine Drain pipe and SS nut and ferrule

This is the drain pipe that exist from the rear of the Douglas 2 3/4hp timing case, it screws onto the distinctive 90 degree union that was fitted to the timing case of most 2 3/4hp models of this era (note: 90 degree union is not included - the one in the photograph is an original Douglas item).  

I have formed the pipe on the one fitted to my Douglas to run inwards to close to the bottom frame rail, then bend through approximately 90 degree and face backwards and down, with a 45 degree cut to the pipe, where the oil drips (this looks nicer).  However, the copper pipe is soft enough  to allow the shape to be changed to fit your own model if different.

The pipe is pre-soldered to a brass ferrule and 7/16" x 20 tpi stainless steel nut (Item 0891_2) - which I found to be the output thread on the 90 degree union fitted to my Douglas model. 

Note: if bending the copper pipe to your own shape - it is advised to hold the copper pipe firmly just ahead of the brass gland - as the brass is very thin at the point it passes through the nut and could split.  If the pipe loosens from the ferrule when bending, it can simply be heated up again with a blowtorch to re-solder the joint

0891_8 Black Rubber distance piece and ferrules

his sub listing is for a 1/4" Bore oil resistent black distance piece, with chrome plated ferrules on both ends.  The overall length of the distance piece will be @2.00" (approx 52mm).

The purpose of this is to allow for small variations in length between models (I think), but also to damp out vibration from the engine, so the pipes are less likely to fracture

It should be noted that this item will come with ferrules which require a petrol/oil pipe crimping tool, to crimp them to the 1/4" bore copper pipe the distance piece is designed to fit over.  However - if required, we can pre-crimp the ferrules for you, so the distance piece is a 'firm' slide fit over 1/4" bore pipe.  If you require this - please leave a note when placing your online order, otherwise the ferrules will come un-crimped.

0891_9 N/A Further Pipes to follow - or email if you have a particular combination you do not see here.  


















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