1955 AJS 500 Twin

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

Postby R_Nairtvm » Thu Jan 25, 2018 4:54 am

Hello All,

I have recently acquired and completed restoration of a 1955 AJS 500 Twin. (not too sure if its 18 or 18s)

Its running well, and is in reasonably tight shape. I believe I have been able to source correct parts in respect of major components both through parts sources and/or through getting them made/machined locally, in Pune and Trivandrum, India

One major item – Amal Carburettor – was sourced from UK; specification was 389/7 which was in fact of 1 5/32” bore and the factory settings were 250 main jet, 30 pilot jet, no. 3 throttle valve cutaway, needle position 3 and a 106 needle jet.

Am attaching pictures of the bike

Image
Image


Any suggestions for improvements are really welcome.
Last edited by R_Nairtvm on Wed Jan 31, 2018 4:34 pm, edited 2 times in total.

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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Thu Jan 25, 2018 3:22 pm

The bike appears to have 1954 wheels. 18 & 18s is a single, 20 would be a 500 twin.You should see year and model in the engine number.

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Re: 1955 AJS 500 Twin

Postby R_Nairtvm » Thu Jan 25, 2018 4:32 pm

Thanks Rob for the correction.

Its indeed a Twin with single carburettor.

I had ordered the replacement Amal Carburettor form the "Burlen Fuel Systems Limited - The SU and AMAL Carburetter Companies" and they led to believe me that the bike is 18 or 18s.

Anyway the Carburettor works fine and has been trouble free so far

I will try and get the engine number verified shortly.

The wheels were missing when I got the bike and was sourced locally from a junk yard. Probably hence the mismatch. Would you happen to have a picture of the correct wheels on even a picture of a complete bike, which I can then use for reference

Best Regards & Ride Safe



Rob Harknett wrote:The bike appears to have 1954 wheels. 18 & 18s is a single, 20 would be a 500 twin.You should see year and model in the engine number.

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Re: 1955 AJS 500 Twin

Postby ajscomboman » Thu Jan 25, 2018 5:31 pm

Regardless of what wheels you have (they are 54 by the way) the front wheel needs to be swapped around with the brake on the left as you sit on the bike. The brake plate torque arm needs to be under tension when the brake it applied and not under compression as it currently is. It's not an uncommon mistake but it is definitely a serious safety issue.

The engine number along with year will be stamped on the left case and will be something along the lines of 55/20 *****

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Re: 1955 AJS 500 Twin

Postby Reynard24 » Thu Jan 25, 2018 5:51 pm

A 389 monobloc of 1 5/32" sounds a bit big - it would originally ('55) have been a type 376 of 1" choke
A 389 1 5/32" is correct for a Model 18 though. If it's running OK then leave it as is.

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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Thu Jan 25, 2018 9:56 pm

I would not be too hasty to change the wheels. Just in case the frame and engine turns out to be 54. 1955 had full width hubs front and back. But fins were conical, not square profile like the one off 54 year front wheel you have. Rear was QD also a one off for 55 only, with metal pins in metal holes. In 56 had metal pins but also rubbers. This prevented a noisy metallic " snatch " in low gear / speed
Ashampoo_Snap_2018.01.25_21h58m55s_002_.png

Ashampoo_Snap_2018.01.25_21h57m58s_001_.png
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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Thu Jan 25, 2018 10:02 pm

Have you considered joining our club. You have limited time using the forum free.

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Re: 1955 AJS 500 Twin

Postby ajscomboman » Fri Jan 26, 2018 11:32 am

No-one suggested swapping the wheels Rob just simply turning the front wheel around so the brake plate is on the correct side. I'm in agreement with you I wouldn't be in any rush to swap them for any other wheels.

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Re: 1955 AJS 500 Twin

Postby Rob Harknett » Fri Jan 26, 2018 11:59 am

ajscomboman wrote:No-one suggested swapping the wheels Rob just simply turning the front wheel around so the brake plate is on the correct side. I'm in agreement with you I wouldn't be in any rush to swap them for any other wheels.

It is related to suggestions / improvements Rob, having pointed out wheels looked like 54 ( not sure about the rear which may be earlier? ) Last thing you want to do is change them and the bike turns out to be 54 and not 55.
The rear end looks like 55 to me, but I have to wonder why that wrong battery box is fitted at an angle.

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Re: 1955 AJS 500 Twin

Postby R_Nairtvm » Sat Jan 27, 2018 6:23 pm

Rob Harknett wrote:Have you considered joining our club. You have limited time using the forum free.


Hi Rob, thanks for your suggestions. I have joined as a member already.

I don't know why its not showing up on my profile laready.

Best Regards & Thanks

Ram Nair

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