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General => Douglas Motorcycle Discussion => Topic started by: KiwiJohn on 21 Dec 2005 at 18:35

Title: About Amal carbs used on the postwar Mark series
Post by: KiwiJohn on 21 Dec 2005 at 18:35
Amal carbs and parts are available from http://www.hitchcocksmotorcycles.com who I have bought parts from and are great to deal with.

John
Title: Re: About Amal carbs used on the postwar Mark series
Post by: Dave on 21 Dec 2005 at 19:49
Thanks for posting this link John. Would you like to also post it in the UK section of Recommended Parts Suppliers (https://www.douglasmotorcycles.net/index.php/board,42.0.html)?

Dave
Title: Re: About Amal carbs used on the postwar Mark series
Post by: MrWright on 22 Dec 2005 at 20:12
Jon,

Thanks for the Amal carb resource at Hitchcock's Motorcycles; however, I must be missing something.  I have not found an Amal carb, model 274 with a vertical mounting bolt pattern.  Al of the carbs shown have a horizontal mounting bolt pattern.  Should I use an adaptor flange?

dave
Title: Re: About Amal carbs used on the postwar Mark series
Post by: KiwiJohn on 22 Dec 2005 at 21:09
Sorry Dave,  I dont think I have ever even seen one with vertical mounts.  My bike has been fitted with adapters and pipe mount type carbs.

I feel one would have to be really picky to criticise the use of an adapter flange.

Hitchcocks were very helpful on the telephone and you never know they may have a source of vertical mount pattern carbs.
Title: Re: About Amal carbs used on the postwar Mark series
Post by: MrWright on 22 Dec 2005 at 22:20
John,

I tend to agree and to further support your statement, Douglas’s were never imported into the US, nobody state-side knows any better!

Take care,
Dave
Title: Re: About Amal carbs used on the postwar Mark series
Post by: alwyn on 23 Dec 2005 at 01:15
Sorry Dave,  I dont think I have ever even seen one with vertical mounts.  My bike has been fitted with adapters and pipe mount type carbs.

Hi John and others,
See here (https://www.douglasmotorcycles.net/index.php/topic,1057.msg3536.html#msg3536st) for standard Amal carburettor (types 274-AJ/AK-4A - AJ/AK designating right and left handing) with vertical mounting flange as fitted to Doug's MkIII and my '48 T35.

Alwyn
Title: Re: About Amal carbs used on the postwar Mark series
Post by: Doug on 23 Dec 2005 at 03:20
Quote
...I don't think I have ever even seen one with vertical mounts.


Well you can see a picture of one here: https://www.douglasmotorcycles.net/index.php/topic,1057.msg3536.html#msg3536

There are plenty of period photos of the Mark series Douglases, where the vertical flanged nature of the carburetor is apparent.  As well as shown in the Mark series illustrated spares list:

(https://www.douglasmotorcycles.net/aa-files/images/doug/2005/mark-carb/20051222-carb-spares-list-0420.jpg)
Large image (https://www.douglasmotorcycles.net/aa-files/images/doug/2005/mark-carb/20051222-carb-spares-list-1000.jpg)

In there it gives the carburetor numbers as: 274AJ/4A, right-hand; and 274AK/4A, left-hand.  These carburetors are not going to be available from Hitchcock’s as they sell new production of the older model Amal carburetors.  The vertical flange style was only used by Douglas, so they are not common enough to be economically viable to reproduce.  Well I say only Douglas used them, but I have heard there was a postwar vertical single that used the vertical flange body, so that they could lay the carburetor body over on it side.  But it only used the one hand, being a mere single (can not remember the make and model) rather than “The Best Twin”.   Other than the body, the rest of the parts should be interchangeable with the more common horizontal flanged 274.  Note that the spares book gives one model carburetor as fitting Mark1 through Mark 5.  This spares list was printed long after the Mark 1 ceased production, in the Mark 5 era, when originality was not a concern.  They give parts that are interchangeable; at the bottom of the list they mention the original types: 74J/4A and 74K/4A.  Some of the components may not be interchangeable between the 274 and the 74 series, you will need a carburetor expert to help you if you need to mix and match.  One visible difference is that the T35, or Mark 1, had a different air intake funnel.  It was capped on the end, the air entered via a series of holes drilled around the periphery.  Also elsewhere on this forum (link to post) (https://www.douglasmotorcycles.net/index.php/topic,1057.msg3538.html#msg3538) (link to pictures) (https://www.douglasmotorcycles.net/index.php/topic,1057.msg3559.html#msg3559) it is mention brass bodied versions are known rather than the more commonly seen aluminum (these brass carbs may be the 74 series, as they have the prewar style air vent.)   

Of course, this all pertains to originality.  It will run perfectly well with any suitable carburetor using an adaptor.   

According to the Plus handbook, Plus models were fitted with the Amal 276EP/1B, right-hand; and 276EQ/1B, left-hand.  Amal TT carburetors could be supplied as an option, as could probably anything reasonable the customer would ask and pay for!  I have not seen a vertical flanged 276 Amal, or TT Amal.  All period photos that I have seen of Plus models where you can see how the carburetor is mounted show a clip-on carburetor, with a flange to stub adaptor.  That is not to say a vertical to horizontal flange adaptor was not available then or shortly after.  I’ve just not seen an old photo of one yet. 

There were some Mark series machines exported to the United States.  According to the Works dispatch ledger my Mark 3 Sports was shipped directly to its new owner in New York City, in May of 1948.  However there were not a lot of machines shipped to the States, forty-some I think between 1946 and 1954 (and at least one 90 Plus that a friend of the family bought after the New York City Motorcycle show.)  There was an article by Jerry Rodgers about export numbers in an old issue of the New ConRod.  There have been far more (Pre- and Postwar) imported by collectors and enthusiasts since, than by the Douglas factory. 

-Doug

P.S.  Alwyn beat me to the post while I was typing this up! 
Title: Re: About Amal carbs used on the postwar Mark series
Post by: trevorp on 23 Dec 2005 at 03:37
the slides are different from mk 1 to mk 3 as the cutaway is different to allow for more flow in mk3 engines onwards
also main jet is different75 on mk 1 80 on mk 3 and the slides are 4/3 for mk 1 and 4/5 for mk 3 on
Title: Re: About Amal carbs used on the postwar Mark series
Post by: aggettd on 23 Dec 2005 at 16:16
Actually I think the horizontal Amals were a bit more common than realized, as according the material I have available, the 1936 AJS model 26 twin port 350, and the Model 8 and 18 500s had a horizontal Amal carb. The horizontals seem to have been fitted only to thes bikes with veritical cylinder barrels. The 1935 models with forward canted barrels all had vertical carbs. I had been looking for some time for a right-handed 274 for my t35 and found one at the Motorcycle Emporium in Australia. Isn't the internet a wonderful thing? The floatbowl is twisted 90 degrees to be upright while the carb lays on its side with the flange in the right orientation for the Douglas, although the vendor gave no indication what bike it had come from originally.

David Aggett
Title: Re: About Amal carbs used on the postwar Mark series
Post by: MrWright on 23 Dec 2005 at 16:50
David,

David

Yes the internet is a wonderful thing.  I get the opinions of people across the world on a subject that is not so common, and we all learn as a collective group.  I am a “weekend warrior” in the field of bike restoration; however, I like to stick with OEM solutions when possible.  I build my bikes to be ridden, and I do not tolerate a machine that “act-up”.  With that said, I always carry a cell-phone when riding and I always venture close to home for the first year of completion (close is 5 miles).  I have printed-out the particular message board, pertaining to carburetors, highlighted the points of interest and here is my plan:  I am going to use Amals with a barrel mount (non-flange), replacing parts as necessary on the carbs shown in my original post (https://www.douglasmotorcycles.net/index.php/topic,1057.0.html ).  I will try to purchase the interface flange, but without dimensioned drawing of the mounting configuration from the suppliers (or a known part number that bolts-up directly) I may machine the flange interface (not a difficult task).  Keep the info coming, and if anyone has a flange part number the mounts directly to the Douglas, please return same.

I posted a pic of a Suzuki restoration (last years project) just as point of reference

(https://www.douglasmotorcycles.net/aa-files/images/mrwright/2005/20051229-suzuki-420w.jpg)

Larger view (https://www.douglasmotorcycles.net/aa-files/images/mrwright/2005/20051229-suzuki-1000w.jpg)