Someone here with knowledge about AMC Twins?

[MG]

Hello!

Sorry about the non-BSA-post, but I thought maybe there are some people on this forum that might be able to help.

I was offered a Matchless G12 CSR from '59 in pieces and I would like to have a look at it within the next few days or so.
So I got a couple of questions:

What should the frame number be for the '59 model? Is there a special number for the CSR frame? I'm aware that the engine number should start with 59-G12CSR-, but I didn't find much information on the frames. What I read is that the rear loops of the
CSR frames are supposed to be shorter. Is that correct? What length should they be then?

If CSR, it should be equipped with mag and dynamo, Lucas K2F or even K2FC? Manual advance I suppose either way?

Speedo: Smiths chronometric I suppose?

Mudguards are supposed to be alloy, right?

Are there any other things I should have a closer look at? Rare/expensive parts? Parts that are likely to fail?

Thanks a lot in advance, any hint will be highly appreciated.


Cheers, Markus


****edit****
If you don't want to officially come out as a Matchless/AJS rider, you might as well send me a PN 

[cus]

G'day Markus,
I've been in a similar situation with a Matchy basket case, & couldn't find much info
on coinciding engine & frame numbers, they seem to be all over the place!
The frames can be AJS of Matchless, engines Norton Atlas with Matchy badges,
forks, Norton road holder, there a bit of a bitza those G12's, but from what I hear,
a good combination, not much help! someone will have more info I'm sure.

regards, Cus

[MG]

Thank you cus!
I guess the only thing one could really check on the frame is, that it is somewhere close to the year of the engine (58 or 59), afaik 1960 brought the duplex frame. I am aware that knowing exactly requires asking for a dating certificate at the Owner's Club.
I think it was in the 60s though, when they started using Norton parts. So this should not apply for the 59 model.

[muskrat]

G'day Marcus, I've got a mate in town with one (Atlas motor) and will see him over weekend. Will ask for info 4U.
Cheers

[MG]

Hello muskrat!
Thanks a lot for the kind offer, but it is too late already.  I've been there to see the bike and was forced to buy it (you know those voices in your head that keep telling you to do such crazy things, don't you?  ).

It turned out to be a genuine 61 AJS 31 CRS. The original british paperwork is still there. The lhs crankcase had been damaged and so the seller got a 59 Matchless G12 case with it, which led him to believe it was a Matchy. This guy collect BMWs (so sorry for using bad language on this forum  ), so his knowledge about Brit bikes is rather small. He exchanged the AJS for a BMW (sorry again) and someone told him Matchies would receive higher prices.
Well, the engine is still in pieces with new bearings, valves and a reground crank, was done by a professional and looks rather good to me. The cylinders were rebored and a pair of NOS Hepolites is included.
Everything except the exhaust has been rechromed and all the paintwork had been done (in Matchless red, after sandblasting), the wheels are assembled with new spokes and rechromed original rims, forks and frame are readily assembled.
The work that has been done so far seems to be pretty good. You could see on the other bikes he had restored (those thing from Bavaria), that he knows what he's doing, so I'm pretty happy with my purchase. The fact that there are loads of new parts also is not particularly bad.

And to top things off I got a set of two TT carbs with an external float bowl and correct manifolds for the CSR heads with it, plus the Monobloc and the 2in1 manifold.

Now I have the choice to turn it back to an AJS with the repaired original crankcase, which would require repainting everything blue, or leave it as it is and fit the 59 crankcases.
Boy, life is full of difficult decisions....

Cheers, Markus

[muskrat]

Lucky bugga, nice score.
Cheers

[groily]

Tempted to say your troubles are only just beginning MG! But the optimist in me says it will be OK in the and you'll be happy.
It's darn hard to track all the model changes year by year and I don't know anything, despite having AMC twins most of my life. But it's good if it's a '61 CSR, all of it. If the engine was a '58 (or maybe a '59), there could be all sorts of issues as one or other year was a one-off, but a '61 has a specification that is intelligible and all the oily bits should be identifiable - and most of them obtainable. I'd say if you've got the right chrome and tinware you're on a winner, as cycle parts are hard. It's not an Atlas engine, it's the last of the line 650 AMC 3 main bearing twins, with some points of weakness (minor things, just crankshafts and stuff) ironed out after the problems encountered with the cooking Mod 31 AJS and Matchless  G12. The G15 was the one which wasn't really an AMC twin, but a Norton hybrid (and I'm not saying any the worse for it if you want to run around with an over-bored Dominator). Who knows who owned whom by that time.
You really need to join the AJSMOC with one of these. I don't say that to try to part you from your money, but the info available is precious and the spares scheme (which sells parts to anyone as a matter of fact) is worth 'joining' for an annual small fee that is repaid with interest on the first order. NOS Hepolites are, I believe, a VERY good thing.
Meanwhile, you might want to look - if you haven't already - at
http://ajsmatchless.webs.com/christiansarchive.htm
which is generally acknowledged to be THE source of info for the marque apart from the club. Pix too.

(Just a thought, but mixing crankcase halves is a delicate thing on these engines, as the centre main bearing rather gets in the way of things. It's amazing how with the centre (shell) main and the drive-side main in place it all turns so smoothly - and then you do up the bolts on the timing side case and lo and behold . . . it doesn't!)

[MG]

Hello groily!

Thanks a lot for the information. I didn't know the link, looks very informative indeed. As a first step I've ordered the Bacon book (AJS/Matchless Twin Restoration). If that one is as good as the BSA book of his, I think it will be a good starting point.
I don't intend to mix crankcase halves, as I have two complete sets, so no problem here. I'm aware that it can take a few attempts until the crank runs freely. I can compare the complete 59 cases to the 61, which had been damaged and were repaired. So I have a chance to pick the better set, have a look at the differences and maybe modify the older one to suit, if necessary. From what I've read so far, there were just minor mods concerning the lubrication system in these years.
The bike is almost complete despite of some small and easily obtainable parts, the crank I got with it definitely is nodular iron, so should be okay for the HC pistons.

We'll see, I'll let you know when she's ready for the road (probably not before next year)  

Cheers, Markus