1955 AJS 500 Twin

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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Re: 1955 AJS 500 Twin

Postby clive » Sun Feb 11, 2018 3:31 pm

Failure of the brake torque arm has I think usually been associated with the retaining bolt coming loose and allowing the arm to chatter and weaken the metal round the bolt hole in the brake torque arm. Alternatively its because the wrong bolt has been used with thread instead of an unthreaded shoulder where it sits in the torque arm. Under breaking this woul soon round off the thread and allow similar chatter. I have seen years ago someone producing a torque arm with a larger amount of material around the bolt hole.
clive
if it ain't broke don't fix

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Re: 1955 AJS 500 Twin

Postby R_Nairtvm » Mon Feb 12, 2018 2:29 pm

Hi Rob,

Thanks for pointing me in the right direction with the referral material on the bike. Its been very useful

Now I need to figure out where/who in India the reproductions are being done (a task which is going to be a bit time consuming as most of these are likely to be in the Central or North regions of India and I am in the south. But I am sure my two wheele buddies would help me with it.

Rob Harknett wrote:So many questions could be answered without any doubt as being right or wrong, by looking in the literature for your bike. In sales cat. & manual you will clearly see the brake torque arm in its correct place. In the sales cat. you will see air cleaner is an optional extra. In the parts list you will see a picture of the air cleaner. ( I think they are being reproduced in India )

You will need to change carb settings if a cleaner is fitted. The change can be found in Amal literature.


Thanks Clive for elaborating on the brake arm failure issue. Will definitely bear your pointers in mind and review the set up and have it changed to the left side

clive wrote:Failure of the brake torque arm has I think usually been associated with the retaining bolt coming loose and allowing the arm to chatter and weaken the metal round the bolt hole in the brake torque arm. Alternatively its because the wrong bolt has been used with thread instead of an unthreaded shoulder where it sits in the torque arm. Under breaking this woul soon round off the thread and allow similar chatter. I have seen years ago someone producing a torque arm with a larger amount of material around the bolt hole.


I am sure with help of experts here, I would be able to get the bits and peices together towards the original form of the bike.

On the "air cleaner" though I am aware that this was an optional item, I saw some advisory in some AJS literature, that its better to use the Air Cleaner in "dusty" operating areas. In that sense where the bike will be used (though sparingly) is indeed dusty. Hence, I am a bit concerned about leaving the Carb intake 'un-protected'.

Till such time I am able to source the correct part, is there any harm in using one like in the picture below ???

Image

Best Regards & Ride Safe

Ram

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Re: 1955 AJS 500 Twin - Side Stand

Postby R_Nairtvm » Thu Feb 15, 2018 6:58 am

I am in the process of getting a Side/Prop Stand for the bike

From the Parts List I have identified the correct stand (I think). Hopefully I will get a used original or a replica.

Now the question is where does it fit on the frame ? Does it go in to the place I have marked in the pic below ?

Image

Please correct me if I am wrong ?? Also any info on availability of one (have put and advert in the spares wanted as well).

Best Regards & Ride Safe

Ram

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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Thu Feb 15, 2018 11:13 am

You are wrong Ram. You show a ridged frame also not where the side stand is fitted.
Ashampoo_Snap_2018.02.15_11h03m25s_001_.png

There is a picture showing the side stand. The stand consists leg, a special fitting to fit it on the frame stand lug. Also a spring that fits on the stand leg and hooks in a hole on the underside of the frame rail further back from the stand lug. The club did sell the stand complete with fittings & spring. I recall the club price complete was cheaper than and old bent leg only, you may find second hand
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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Thu Feb 15, 2018 11:17 am

It looks like the club only has the side stand special bolt and spring now. The complete stand seen is only for a lightweight bike.

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Re: 1955 AJS 500 Twin

Postby R_Nairtvm » Thu Feb 15, 2018 2:11 pm

Hi Rob,

I got the pic from Spares List (see below) that was on - http://www.archives.jampot.dk/

Image

Is this the right Spares List I should be looking at ? If not can you please point me the right direction

Rob Harknett wrote:You are wrong Ram. You show a ridged frame also not where the side stand is fitted.


Its a pity that the side stand assembly is now not available in the club, I will keep looking for it elsewhere

Rob Harknett wrote:There is a picture showing the side stand. The stand consists leg, a special fitting to fit it on the frame stand lug. Also a spring that fits on the stand leg and hooks in a hole on the underside of the frame rail further back from the stand lug. The club did sell the stand complete with fittings & spring. I recall the club price complete was cheaper than and old bent leg only, you may find second hand


Best Regards & Ride safe

Ram

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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Thu Feb 15, 2018 2:49 pm

The book is correct, but you marked the place you thought the stand fitted on the rigid type rear frame, wrong rear frame also wrong place for the stand. I have marked parts of the frame you have, which has separate front rails and swinging arm.
Ashampoo_Snap_2018.02.15_14h43m12s_001_.png
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Re: 1955 AJS 500 Twin

Postby SPRIDDLER » Thu Feb 15, 2018 3:16 pm

R_Nairtvm wrote: On the "air cleaner" .........Till such time I am able to source the correct part, is there any harm in using one like in the picture below ???

That'll be O.K. Ram. You can use any air cleaner that will fit in the space available and where its 'throat' or the area of its 'cut-outs' isn't less than the carb throat area.
Whichever filter you fit you will have to change the carb jetting. A smaller Main jet will be necessary or the mixture will be too rich. The size of main jet that does the job will depend upon the fineness of the filter and how much it reduces/restricts the air flow into the carb.
I poke badgers with spoons.

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Re: 1955 AJS 500 Twin

Postby R_Nairtvm » Fri Feb 16, 2018 7:50 am

Hi Rob,

Thanks. I realised it myself when I revisited the book, post your comment. Thanks for marking the correct ones.

Rob Harknett wrote: I have marked parts of the frame you have, which has separate front rails and swinging arm.


Thanks Spriddler,

The Air Cleaner can be married to the throat of the carb with out much problem I think - probably the old RE Bullet rubber connector would do the trick.

The bigger problem now would be deciding on the jetting

Current Set up (without filter) - its running well - its a brand new Amal Carburettor from Burlen Fuel Systems Limited
389/7 1 5/32” - 250 main jet, 30 pilot jet, no. 3 throttle valve cutaway, needle position 3 and a 106 needle jet.

As per WS/Owners Manual – (http://archives.jampot.dk/book/Owners_m ... Manual.pdf)
376/6 - 240 Main jet (without filter), 230 (with filter), Pilot Jet 30, Needle position – Centre Notch Throttle valve 4, Needle jet size 1065

As per Amal carburettor info – (http://archives.jampot.dk/technical/Car ... nd_use.pdf)
AJS 498cc 1955-58; 20 Twin - 1" 30 4 220 0.106 3

I guess I will have to experiment with jet sizes and get it right

I may be going in for a replica "Made in India" AJS filter itself

SPRIDDLER wrote:That'll be O.K. Ram. You can use any air cleaner that will fit in the space available and where its 'throat' or the area of its 'cut-outs' isn't less than the carb throat area.
Whichever filter you fit you will have to change the carb jetting.

Best Regards & Ride Safe

Ram

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Re: 1955 AJS 500 Twin

Postby R_Nairtvm » Mon Feb 19, 2018 3:05 pm

The current colour scheme of the bike is as below
Image
Was this ever a "factory offering" ? The badge currently on the tank - I believe it was offered only with "chrome plated tanks". Right?

I have seen various AJS stylisations on the tanks - as in the combo pic below (only couple of them are twins though)
Image
Which style is more authentic for a 1955 Twin ?

Best Regards & Ride Safe

Ram

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