new AJS Model 31 owner

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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new AJS Model 31 owner

Postby BritBikerDan » Mon Jan 18, 2021 5:32 pm

Hello All and Happy New Year!
I am in the process of importing a lovely, restored 1960 AJS Model 31 Deluxe from the UK (Cornwall, actually) which I am very excited about. I am far from new to British bikes; I have 5 BSA's (650 twins and a 441 single) and a '68 Triumph Bonneville but never had an AJS twin until now. I am looking for anyone's thoughts about "do's and don'ts" pertaining to this model. The bike was restored in 1999 yet has logged only about 5,700 miles since that time so I reckon it's simply now broken in.

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Re: new AJS Model 31 owner

Postby clive » Mon Jan 18, 2021 9:50 pm

Hi and welcome to the club. You will have good service from your AJS but one issue may be a problem which is that the twins tend to wet sump if not used regularly. This is unlikely to be a problem if used once a fortnight or perhaps once a week. Symptoms of the wet sumping are difficulty starting and smoke once it gets going, soon clearing. If you do decide to fit an oil tap please arrange one which has a linked switch to earth the ignition so you cannot start it until the oil is on.
Other than that you will soon wonder why you have been wasting all those years with BSAs :rofl:
clive
if it ain't broke don't fix

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Re: new AJS Model 31 owner

Postby MalcW » Tue Jan 19, 2021 9:27 am

Hi, and congratulations on your new purchase. I've had one for about 3 years, a magneto/dynamo version, and I love it.

As far as Do's and Don't are concerned, Do consider replacing the centre stand, as the standard one can be hard work, and Don't be surprised when you apply the front brake and not much happens... It's not really that bad, but will probably be weaker than you're used to. As has been said already, there will probably be a tendency to wet sump if not used for a while, but that's normal.

Above all, Enjoy!

Malc

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Re: new AJS Model 31 owner

Postby mdt-son » Wed Jan 20, 2021 6:52 pm

Hi Dan,

Importing a bike from the UK to the USA? Now that requires a determined mind! Most bikes are shipped in the other direction.

I trust you have done your homework, especially the chapter covering the oiling system and preventive maintenance wrt. the oiling system?

Fitting an external cartridge 10 micron oil filter is highly recommended. Look for reports in this forum.

Do you have a detailed record of what was done during the 1999 restoration? Were conrods machined and the crankshaft magnafluxed and ground? Please read reports in this forum.

The front brake, though only a narrow 7in SLS one, can be made to lock up your front wheel ! There is no big engineering challenge involved in creating a duo-duplex brake, should you feel the need to improve effectiveness and cooling (details available on request). Please find picture of a 2LS (or TLS) brake conversion below. An hydraulic front brake conversion has been made in the past (report available).

I trust you will find the Club and this forum very helpful.

Best of luck and have fun with this lovely bike!

-Knut


2LS brake by Arne Eriksen.JPG
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Re: new AJS Model 31 owner

Postby BritBikerDan » Tue Jan 26, 2021 7:52 pm

I appreciate the reply from Clive about the wet sumping issue. I am very familiar with this phenomenon in BSA twins. When I receive the bike from the UK I will drain the sump and, if the oil appears clean which is probable (the seller took meticulous care of it) I'll pour it back in the oil tank.

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Re: new AJS Model 31 owner

Postby BritBikerDan » Tue Jan 26, 2021 8:17 pm

I enjoyed reading Knut's thoughtful reply to my "do's and don'ts" post. I was motivated to buy an AJS or Matchless twin in the UK because I was beginning to despair of ever having the opportunity to buy one here in the States; they are that rare over here! I've been waiting and watching, off and on, over the last 25 years and finally decided to cast a wider net, over the pond, and was rewarded with a good catch.
I have an owner's handbook as part of the purchase which I have already received and will be reading in detail between now and the time the bike actually arrives here in mid-March. Regarding oil filters, I have wrestled with that idea with my 650 BSA's for a long time and have never pulled the trigger. I probably won't in this case either. I change oil often to keep it clean and doubt that I will put more than 500-1000 miles on it the first year. It will be ridden in rotation with my other classic bikes during our short riding season here in Colorado.
For once I do have detailed records of what was done during the 20+ years ago restoration. As far as I can tell it has only been ridden about 5000 miles since that time. There is no mention made of your question regarding the machining of conrods. It does specify new main bearings and big ends. I would imagine that the crankshaft was re-ground to accomodate the new big end plain bearings.
The photo you sent of the TLS front brake conversion is quite impressive! I will have to see how the front brake actually is when the bike is in my hands and I have a chance to ride it before deciding to make such a conversion.
I am already enjoying the Club and glad to finally have a chance like this to join the fraternity.

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Re: new AJS Model 31 owner

Postby BritBikerDan » Tue Jan 26, 2021 8:22 pm

I was intrigued by Malc's reply especially concerning the center stand. Ironically, Stephen T., the seller, gave me as one of his reasons for selling the difficulty he'd had getting the bike up on its center stand! From what you wrote I have a hunch that there's a later/better centerstand available for these bikes? If so, I'd like to learn more about how to obtain one.

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Re: new AJS Model 31 owner

Postby clive » Tue Jan 26, 2021 8:44 pm

OH dear we have a rule in our club about not advertising on the open forum (there are adverts and an advertising section) and usually as the officer charged with policing this rule I have to step in to tell the President off for breaking the rule. On this occasion I have beaten him to it. have a look here for his roll on roll off stand http://www.jampot.com/ads_G_TRADEList.asp?ScrollAction=Page+3&DUMMY=Tue%2C%2026%20Jan%202021%2020%3A40%3A36%20GMT
clive
if it ain't broke don't fix

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Re: new AJS Model 31 owner

Postby SPRIDDLER » Tue Jan 26, 2021 9:47 pm

BritBikerDan wrote:I have an owner's handbook as part of the purchase which I have already received and will be reading in detail between now and the time the bike actually arrives here in mid-March.

Welcome Dan.
Plenty more reading (original Owners and Workshop manuals, spares lists etc. under 'Books') in the link below for 'Christians Archive' (if you haven't already found it).......

http://archives.jampot.dk/

Lots more interesting stuff to enjoy while you're waiting, under the other Archive headings; (Editorial, Technical etc.)
E.g. tales and photos from the factory here:

http://archives.jampot.dk/general/Working_for_AMC.pdf
I poke badgers with spoons.....from 2 metres.

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Re: new AJS Model 31 owner

Postby MalcW » Wed Jan 27, 2021 8:55 am

BritBikerDan wrote:I was intrigued by Malc's reply especially concerning the center stand. Ironically, Stephen T., the seller, gave me as one of his reasons for selling the difficulty he'd had getting the bike up on its center stand! From what you wrote I have a hunch that there's a later/better centerstand available for these bikes? If so, I'd like to learn more about how to obtain one.


There is. I see Clive has already posted a link to the Services section. Me & a mate both have them, and they work! (No connection, just a satisfied customer).

Malc

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