Villiers midget carb query

Hi gents,

I'm.currently renovating a 1947 Allen Oxford powered scythe, which has a Villiers 11c engine.

The carburettor has a male threaded fuel inlet rather than a female thread and banjo.

Does anyone have an idea of the thread, its 26 tpi so I'm hoping its gas thread.

Regards

Mick

26 tpi is a very common pitch, used for many BSC (British Standard Cycle) threads of varying diameters. 1/4 BSF is also 26tpi.

Motalia have printable charts which you can download to check. There is also the possibility that it is a Villiers carburettor proprietary size.

**LINK**

Edited By old mart on 25/01/2020 21:58:20

There is no British Standard Pipe thread with a 26 tpi pitch.. 1/8 BSP is 28 tpi. Above 1/8 it goes to 19 tpi and then to 14 and then 11 tpi.

If the thread form is 60 degrees, it will be British Cycle thread.

There are no Unified Coarse or Fine with 26 tpi pitches. And, given the age, a Unified thread would be unlikely.

If the form is 55 degrees, it may well be British Standard Brass, Only 1/4 BSF is 26 tpi

What is the OD? Presumably, given the age, Imperial.

Howard

Hi all, OD is about half inch. The guy at villiers parts says no one he knows has ever identified the thread. Luckily he had a nut and nipple to suit so I bought that and we are up and running now.

Many thanks for the comments.

Mick

I had an Atco mower with a Villiers midget engine, and when it fell to bits, the carburettor got put on one of those sixties mopeds with the two speed gearbox. I can't remember the make, but it did 35 mph after the mod.

Villiers were quite keen users of their own thread forms. Their later, larger carburetters incorporate a whole range of different standard threads e.g. BSF, BA, BSC as well as their own threads.

Chas

Could be British Brass Thread. 26tpi all diameters. 55 deg form.

The main thing is that you are up and running.

But it would have been interesting to know what the thread is. (You never know, you may need the info at some time in the future! )

Howard

As an update I had some problems getting it to run right.

I'm not a whiz with 2 strokes but I was told to re-do the timing from start to finish to make sure it was spot on.

I found I had made a fluff somehow and the timing was out a bit, I completely redid the whole job and now it runs really well.

I'm really pleased I managed to conquer this old tech, never been into bike engines etc so I have learned a lot.

Mick

One of my multifarious jobs as a schoolboy saving up for a motorbike was cutting the grass at a caravan park with an Allen Scythe. Sometimes the clutch was reluctant to disengage and it would drag me around with heels dug in acting as a 2 furrow plough until I managed to get the damn thing to release.

The Allen Scythe could be a right B*****d they did have a habit of digging in on uneven ground. My Grandfather broke his leg with one that dug in. Health and safety would go ballistic at one nowadays but still a great tool for clearing a rough area of undergrowth.

John