1955 AJS 500 Twin

Information relating to the Matchless G9 or AJS Model 20 500cc twin
Locked
G15 Roy
Member
Posts: 3546
Joined: Sun Jan 01, 1995 12:00 am
Location: ESSEX UK

Re: 1955 AJS 500 Twin

Post by G15 Roy »

Do you thinks this would be the one I need to look for.

NO
Roy
User avatar
Rob Harknett
Member
Posts: 11236
Joined: Mon Jan 01, 1990 12:00 am
Location: ESSEX UK

Re: 1955 AJS 500 Twin

Post by Rob Harknett »

plate looks like it is chrome plated so later than 55. You can tell 55 from pulling the wheel off, for 55 only metal pins go in metal holes no rubbers.
R_Nairtvm
Posts: 41
Joined: Thu Jan 25, 2018 3:42 am
Location: India

Re: 1955 AJS 500 Twin

Post by R_Nairtvm »

Hi All,

I used the online dating services and have now established that it is a 1955 Frame. Model 55/G3LS. So that's good, and in that sense papers are in order.

Now I would slowly work towards making sure all components and fittings conform to that of the model year 1955. I am not aiming for any concourse levels but inclined more towards reliability in using it.

1st step is to get the front brake switched to the left side. I saw the picture of anothr G20 in Photos section, where the Front brake was on the right side exactly like mine (the bike of member Kelvin). There was some comment on that as to why people switched to do that - something about some niggle with the brake activation arm - torque arm ??(pardon me as I cant remember the correct name of the lever on the hub drum).

The Comments were as follows

Quote:
"By ajscomboman
06 Feb 2015
Oh dear another bike with the brake assembly on the wrong side. The brake toque arm needs to be in tension not compression when the brake is applied. Dangerous, very dangerous!
By altette
07 Feb 2015
Nice old tool - I bet it sounds 'Rorty' with the single megga...The transposed brake assembly seems to be a popular 'Mod' - I guess owners have heard that the torque arm fails occasionally (with nasty results) and try this alternative arrangement to avoid the problem...
Unquote:

Any thoughts on that ?


Best Regards & Ride Safe

Ram
Last edited by R_Nairtvm on Sat Feb 10, 2018 6:43 am, edited 1 time in total.
leswaller
Posts: 615
Joined: Sun Nov 25, 2012 9:40 pm
Location: Chipping Norton

Re: 1955 AJS 500 Twin

Post by leswaller »

Thats correct, if the brake torque arm is in compression it can bend, if it is in tension then everything is down to the shear strength of the metal involved, and the force required will be much greater than that required to bend the metal.
Les
Rules are for the obedience of fools and the guidance of the wise
R_Nairtvm
Posts: 41
Joined: Thu Jan 25, 2018 3:42 am
Location: India

Re: 1955 AJS 500 Twin

Post by R_Nairtvm »

Thanks for your explanation
leswaller wrote:Thats correct, if the brake torque arm is in compression it can bend, if it is in tension then everything is down to the shear strength of the metal involved, and the force required will be much greater than that required to bend the metal.
I am not person with much of "engineering" background, hence couple of questions for you to answer if you like

In the picture below; the one on the left is on tension (as in my bike) and one on the right is compression, am I right ?? If its otherway round my next question would stand answered

Image

I am sure that jury may be still out on this as to which is better, but question is - other than the point of conformity with the original, why is this - brake arm set up on the right side - being described as dangerous ? Because of the shear strength of the metal involved being suspect ?

Would like the seniours views on this, please.

Best Regards & Ride Safe

Ram
SPRIDDLER
Member
Posts: 8542
Joined: Wed Sep 01, 2004 1:00 am
Location: WEST SUSSEX UK

Re: 1955 AJS 500 Twin

Post by SPRIDDLER »

R_Nairtvm wrote:In the picture below; the one on the left is on tension (as in my bike) and one on the right is compression, am I right ??
No, it is the opposite.
When the brake is applied the brake shoes/linings and the backplate try to rotate in the same direction as the wheel. With the brake fitted on the right as on your bike there is a risk that the torque arm will buckle (bend). This will not happen if the brake is on the left as the torque arm will be under tension.
Last edited by SPRIDDLER on Sat Feb 10, 2018 9:50 am, edited 6 times in total.
'There is a tide in the affairs of men
Which taken at the flood............'
User avatar
clanger9
Posts: 1165
Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: 1955 AJS 500 Twin

Post by clanger9 »

Hi Ram,

In your setup, the torque arm isn't strong enough to resist the braking forces. During heavy braking, the compression force on that little bar will be equivalent to several hundred kg and it will bend, possibly resulting in a nasty accident.

Now look at the correct setup. You can pull on that arm with a tonne of force and it won't go anywhere...
1989 Moto Morini Dart 350
1993 Ducati 750SS
SPRIDDLER
Member
Posts: 8542
Joined: Wed Sep 01, 2004 1:00 am
Location: WEST SUSSEX UK

Re: 1955 AJS 500 Twin

Post by SPRIDDLER »

To add (unnecessarily perhaps) a bit more information:
When you change the brake to the left side you may find for a while that it is less effective than it was previously. This is because if it had been used for some time on the right the linings (particularly the one which was previously the 'leading' shoe will now be the 'trailing' shoe) and will have 'bedded in' accordingly. It should improve after some miles when refitted on the left.

Here is some detail about front brake performance and improvement which I posted 5 years ago and which may help to identify and explain the importance of which are the leading and trailing shoes.

http://www.jampot.com/forum/viewtopic.p ... 66#p115566
'There is a tide in the affairs of men
Which taken at the flood............'
R_Nairtvm
Posts: 41
Joined: Thu Jan 25, 2018 3:42 am
Location: India

Re: 1955 AJS 500 Twin - Air Cleaner

Post by R_Nairtvm »

Hello All !

Have another question (as usual :))

Did the bike come with an Air Cleaner as an OE fitting? Or was this an optional one ??

My bike doesnt have one at the moment and am thinking of fitting one, as there's a fair bit of dust around where I would be operating the bike. If I can source an original one I may have to fashion one from one of the modern paper filters available.

Your thoughts on this please

Best Regards & Ride Safe

Ram
User avatar
Rob Harknett
Member
Posts: 11236
Joined: Mon Jan 01, 1990 12:00 am
Location: ESSEX UK

Re: 1955 AJS 500 Twin

Post by Rob Harknett »

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 )
Ashampoo_Snap_2018.02.11_11h51m26s_001_.png

You will need to change carb settings if a cleaner is fitted. The change can be found in Amal literature.
You do not have the required permissions to view the files attached to this post.
Locked