Matchless – Chasing Motorcycles

Timing the Magneto on your Matchless G12CSR

I read the manual on re-timing the ignition on the big twins (non-Norton). Here is my mild re-write with some extra thoughts.

To re-time the ignition – Twins (Magneto Models). Before proceeding to time the ignition, check the breaker point gap, which should be from .012” to .015”. Ensure that this is done first, as it will affect the advance point if you do it after.

Loosen the nut from the magneto driving gear, and release the gear from the tapered end of the magneto shaft with the correct extractor (part number 015374 – also used for the small crankshaft gear if that ever needs to be pulled).

Remove the inlet rocker cover and spark plug from the off-side cylinder (that’s the right-side of the bike). Insert a rod into the spark plug hole, or if you have it, a dial indicator gauge (if you’re really cool), or a spark plug timing tool as is available on eBay or other outlets (see pic).

Turn the engine in its normal direction until you have found top dead centre after the inlet valve has closed.

Hold the rod in the plug hole, and mark the rod where you can see it register, or mark your dial indicator, adjust the tool, etc… Take out the rod if you’re using it, and mark it higher up 3/8in (9.5mm) for the 500/600cc twins, or 11/32in (8.7mm) for the 650cc models. Put the rod back in (you DID keep it at TDC, right?) and rotate the engine backwards until the higher mark is at your registration point.

Put the ignition control lever on the handlebars in the fully advanced position.

DO NOT Disturb or move the engine. Turn the magneto in a clockwise direction (looking at the contact breaker side, not the shaft side. Keep turning until the contact breaker points are just about to separate as the fibre block moves against the cam.

You can use a piece of cigarette paper or similar super-thin paper between the points to do this, or a test lamp. When it separates, you’re at the exact right position. Press the magneto driving gear back in and lightly tighten the securing nut.

Recheck the timing by repositioning the piston and then tighten everything down. You can check with a degree wheel if you have the engine far enough apart.

3/8” = 39º 11/32” = 35º

And Bob’s your Uncle.

Matchless G12 (’60/’61) Wiring Diagram

I created a wiring diagram for my 1961 G12 Matchless that has colors and makes more sense to me. This is for all AJS/Matchless Twins produced in 1960/1961 with dynamo. Other diagrams (not in color) are in the workshop manuals.

Matchless/AJS wiring Diagram for Magneto Twins

Wiring Diagram — Matchless/AJS Magneto Twins, 1960-1961 (PDF)Download

Matchless Twin Oil Pump Wet-Sumping fix

Matchless G12 Twin Oil Pump Wet Sumping fix, Step by step with instruction download

Since I have the engine of my ’61 G12 apart, I looked up the “Wet Sumping Fix” for Matchless Twins that involves adding O-Rings to the shafts around the input side of the pump. I decided to video the steps I took to share. The instructions on how to do this are in the Jampot Archives or I updated their copy here.

First, you need to remove the input side of the oil pump. While I’m sure you could do this while the pump is on the engine, I think it’s just easier to pull everything, take it apart, clean it and then put it back on the bike.

You only have to do the input side of the pump. There are “two pumps” on the oil pump, one that puts oil “into” the engine from the external sump, and another that takes oil “out of the engine and returns it to the external sump. We are only concerned with the input side. It is the smaller of the two, and is located on the intake side of the engine. DO NOT MIX THESE UP when reassembling.

This first video, I have disassembled the pump and I’m preparing the plate that will be counterbored:

Preparing the Input Pump plate for counterboring

Plate, ready for counterboring. I explain what gets machined, and what to skip.

O-Rings, Honda parts.

Once you have the plate all nice and clean and flat, you can get your 9/16 counterbore with 7/16 pilot and prepare your drill press (I guess you can do it hand-held in a pinch, but depth is critical. Make sure the depth is equal to the width of the O-Ring).

Counterbore installed, preparing to clamp everything down!

Once you get everything together, clamp everything down into a vice, line stuff up, check twice to make sure the pilot goes in and out of the hole smoothly so the cut will be correct. Use the depth gauge on the drill press to make damned sure you don’t go too deep. It’s better to go shallow, then check with a decent set of vernier calipers. I did this. It ended up being 1/128 in short, so I was able to just touch it one more time to make it perfect!

Everything aligned and ready to go.

First one complete

1/16 in. depth. I initially drilled it 1/128 short, then measured with my calipers

Action shot of the last counterbore on the back side of the pump plate.

Finished cutting, time to de-burr and clean.

Assembled, showing external O-Ring that will fit on the camshaft-side.

That’s about it. Follow the steps in the instructions, and I hope the videos explain the step-by-step procedures and break it down for you.

1956 AJS 16MS

“Restored a number of years back, but still looks great. Recently gone through. Runs Great.”

A Very nice 350cc Ride in the Inland Empire (near Temecula, CA)

Seller writes: “Rare 1956 AJS 16MS 350cc. Motorcycle is in incredible condition and sat many years in a private collection. Restored a number of years back, but still looks great. Recently gone through. Runs Great. Clean Title. Come take a look. Would trade for scrambler (triumph, Ducati) Bought through eBay in 2011 for $7000. Big price drop, so no low balls. Only selling to get a small trailer or offload style motorcycle.”

Find it on Craigslist here: https://inlandempire.craigslist.org/mcy/d/murrieta-rare-1956-ajs-16ms/7250377858.html.

This really does look like a clean restoration. I spotted a few nits, but really not that much. These are great riding bikes that will happily zip along at 60 mph, and they handle very sweetly.

The “S” stands for “Springer”.

The rigid framed AJS Model 16M 350 cc single was developed in 1945 from the military Matchless G3/L World War II motorcycle. Well proven in war service, the 350 cc single remained in production selling large numbers to the civilian market well into the 1960s. Simple and practical, the Model 16 needed minimal maintenance and was very economical. The company also produced an almost identical motorcycle under the Matchless name as the Matchless G3L. The only difference between the two was that the Matchless carried a magneto at the rear of the cylinder barrel, whereas the AJS magneto was at the front.

In 1953, the Model 16M was modernized with a dual seat replacing the saddle and rear pillion seat. In 1956 the Burman gearbox was replaced with a new four speed unit of AMC’s own design and in 1957 further improvements included replacement of the outdated generator with a crankshaft mounted Lucas alternator. The leaky pressed-steel primary drive cover was replaced with an alloy casing.

1951 Matchless G80 on Craigslist (CA)

Looks like it’s all there, but it needs some work. Bolt-on hard tail…

1951 Matchless G80 hard tail for sale in Carpinteria (1/4/2021) — https://ventura.craigslist.org/mcy/d/carpinteria-1951-matchless-ajs-g80-18s/7246124644.html

This is represented as a 1951 Matchless G80. It has a “bolt on” Hard-tail frame and at this point is “not street legal”. Buyer says “Alloy fuel tank has a few dings. Needs a few things to be street legal but runs/stops fine. OG CA ‘pink slip’ included. Not registered. $3400…”

I personally own a ’66 G80 and love the bike. It is more fun than anything I own, and can best be described as “easy”. This one needs a lot of love and the price is probably a little high for something that isn’t described as a “runner” and in reasonably good shape.

Parts are plentiful, and the club has a deep, deep catalog of spares, along with AMC Spares. Nothing is dirt cheap, but you’ll be surprised how reasonable it is to own.

Plus the singles had crazy mouse-trap valve springs you just have to love.

Bike is located in Ventura/Carpinteria. At this point it has been on Craigslist here for 23 days.