Hello everyone,
Time to trawl your wonedrfully generous expertise once more.

I am looking for a new carb for the WM20 and was wondering what the correct model is?

I have asked Amal and they have quoted either a 276C/1B or 276L/1E
I have caled them to ask if this would be 'correct' for the bike and if so, why two options but they are a little vague.

Can anyone help point me in the right direction as which one I should ask for.
Thanks............again
Darren

email (option): dwrudd@lineone.net

Both my WM20 parts lists quote 276C/1B. I see from Amal's list that the quote both those numbers, but I have no idea why. The 1B and 1E numbers refer to the float bowl. Probably 1E has a spigot fitting and 1B has a banjo? Banjo is correct for our bikes. Ron

email (option): ronpier@talk21.com

Ron's exactly right. The 1B is indeed the banjo type, as confirmed by the old Amal lists. This confusion goes back to at least 1954 and both types are shown for the ex-WD M20 in the Amal parts list of that year.

I'd suspect that there was a build card made at some time during the war including the (cheaper ?) spigot fitting and that whilst it was never used, it somehow became incorporated in the parts lists.

Thank you guys
I will have one on order Monday morning
Darren

email (option): dwrudd@lineone.net

Well Darren could tell them what he's found out when he orders one. But I expect it will fall on deaf ears.
Like telling Armours their exhausts don't fit

Ron

email (option): ronpier@talk21.com

The guy was very pleasant but did not know what the difference with his own carb references was!!

I will pass this on and crossed fingers it will sink in


Thank you everyone.

email (option): dwrudd@lineone.net

The information that Burlens have is based on the old Amal publications from sixty years ago. We can't really expect them to be experts on every model of motorcycle on their lists. Did some late WM20s have a spigot fitting ?

Next time I'm in the archives, I'll try to research the M20 carb specs.

I have a 1E float bowl and it is also the banjo type. The difference is the length of the attachment arm. Supposedly the early WD types had the float bowl under the petrol tank instead of on the outside. You'll probably need a longer arm to clear the magneto.

Regards,
Leon

email (option): leonhop3@planet.nl

I've had another look at the 1950s Amal listings which I based my initial comments on and certainly have the impression that by then the 1E had the spigot fuel feed. The Amal system was chaotic. I wonder if a post-war 1E might actually not have been the same thing as a pre-war 1E ?

Nortons used the banjo fitting 1BE which is a 0° short arm.



In this listing, the 1E parts list includes a 'Seating Locknut' and the 1B doesn't. The 1B does however include the following parts :-
Banjo Connection, Banjo nut, Banjo union washer.

I remain confused. I hope that someone more knowledgeable can sort it out.

I'm even more confused now. Firstly, Burlens don't seem to list a 1E in their float chamber spares.

However, they do indeed list two carbs for the M20 - the 276C/1B and the 276L/1E This reflects the 1950s listing.

The only difference between the 'C' and the 'L' bodies seems to be that the 'C' had the 6/033 mixing chamber nut and the 'L' had the 6/062.

I 'know' that the 033 is the short mixing chamber nut so assume that the 062 is the longer version.

Was there a specification for the M20 involving a longer mixing chamber nut (this would lower the float level and perhaps improve economy and reduce overflowing)...and did this lower float chamber need a longer arm to clear the mag, as Leon suggests ? Someone out there must know !

OK, most WD M20 had the 276C/1B, 1B denoted that the bowl had two horizontal cross drillings on the brass needle seat under the chamber (four holes) and this was covered by the horizontal elbow which was held on by a nut, the brass threaded part also had the first bit plain and was not threaded all the way. Also listed for WD M20 was the 276L/1E and I have only ever seen one carby marked this in Australia in twenty years of refurbishing these carbs. However I have some new old stock 1E complete bowls which were left behind in India at the end of the war by the British Army and some boxes of a gross (144 items)were sold off to various persons. These bowls are different to the 1B in that they have no horizontal drillings for provision of the fitting of the horizontal elbow and nut and also have the thread on the entire length with the thin nut against the bowl.They are also about half an inch longer in the arm length than a 1B or a 1A bowl. I often see these types of threaded all the way bowls with the two drillings which were done later to fit the horizontal elbow. Another point is that the float chamber was caste over this brass fitting so really the thin nut underneath was useless as it served no purpose. Many a person has undone that nut and tried to hammer the brass fitting out without success or broken the bowl. Also there is not much written down about Amal carbs overall such as the fuel level on the needle jet,difference in the length of the bottom bolt holding the 276 carb compared to the 289.I often find carbs that have say a mono block throttle needle in a 276 which due to its extra length is blocking off the fuel.
Regards John

I think the close up picture in the post about the brazed on casting for the field stand proves that indeed the float bowl sat on the inside and indeed it had a spigot fixing instead of a banjo fixing. I will double check my 1E float bowl because I am beginning to get the feeling that I got it wrong and it's indeed a spigot fixing.

Regards,
Leon

email (option): leonhop3@planet.nl

To throw a spanner in the works my recently acquired WM20 has an Amal 276/014R carb fitted. When I search google I can find reference to it being a BSA fitment and the bike seems to run fine with it fitted.

But, whilst not original to the bike is it the completely wrong carb? Should I be looking at Stafford on Saturday for the previously mentioned Amals?

Any guidance appreciated.

Stuart

email (option): stu.gibbins@btinternet.com

No spanner in the works, Stuart. It's exactly right and is how the carb was originally numbered before Amals revised their system at some pint mid-war.

A rivet counter would give bonus points for that carb on a 1940 or 1941 machine.

The system as I understand it was,Amal started in 1929 and had no throttle stop adjustment screw for that year, 1930 they introduced the throttle stop adjustment screw,all carbs were brass up till 1933 only,they then went to the alloy 4 hole body till 1938. In 1939 the War Office in London demanded that they change so that an air filter could be fitted and so they changed the body to the waterproof type which meant one large hole at the front and got rid of the four holes around the base. In 1929 bodies were marked for instance 6/014,1933 changed to 76/014,1939 with introduction of waterproof bodies changed to 276/014, 1940 on 276C/1B. The mixing chamber body part number for a 276C/1B was listed as a 276/014R and if you got a replacement body as your one was worn out it was stamped 276/014R. I believe the R stood for replacement body and not Racing as some Ebay sellers would have you believe. This numbering system was confirmed by a guy who sold Amal carbies up to 1970's.
So a 276/014R body would be correct for a M20.
Anyone got any different ideas?
John

As a rugby league fan, I don't normally say this to an Aussie, but wow !

It never ceases to amaze me, just how much knowledge people are willing to share on here.

Thank you John, top bloke, ( for an Aussie )

email (option): dwrudd@lineone.net

This carb information should be in the 'Technical Section' for reference. Henk will put in what you send him....Ian

email (option): ian@wright52.plus.com

It is my understanding that the R in 276/014R stood voor a "revised" design.

If you look in the BSA parts books you will see:
M20
1937
76/112
1938
76/014
1939
76/014 for the home market (M20 standard and De Luxe)
276/014R for export (M20 Standard and De Luxe)
1940
76/014 home
276/014R export

This is in the AMAL books:
AMAL settings list 1939
WD M20
276/014R
M20
76/014

AMAL Settings list 1940-1954
WD M20
276L/1E 1940-1945
276C/1B 1940-1945


Regards,
Leon

email (option): leonhop3@planet.nl

Rik

A rivet counter would give bonus points for that carb on a 1940 or 1941 machine.

email (option): stu.gibbins@btinternet.com

PM sent. Ron

email (option): ronpier@talk21.com