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#840560 02/19/21 11:15 pm
Joined: Dec 2014
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I have a 1962 G12 CSR Matchless Monarch. Probably a princess. I have advertised this for sale off and on for several years. Ebay a couple of times, Craigslist, this forum, and at meets/shows with a sign. I got an offer of $3500 a couple of years ago on Ebay, which I declined. At the time, I thought I could get more. I couldn’t. I got a second offer last year for $2500 through this forum, which I also declined. I understand that its value is hurt by its “non-standard” trim. I have since removed the regulator/rectifier and kickstart lever. So it is also no longer operable. It also hasn't been started in at least 3 years and not ridden for longer. So it is no longer for sale. I have decided to keep it and further modify it.

The parts of this bike are clearly worth more than the whole. I recently saw a decent complete set of forks get bid up to and sell on Ebay for $605. First set I ever saw on there. Came up when I was looking at Norton fork parts. I sold a good fuel tank a few years ago for $500. I have also already sold off some other original parts. I could break it down and easily sell off some of the more marketable parts, but that would require considerable effort on my part for a few dollars. So that’s out.

In my opinion, this is not a good road bike. It shakes like hell. The performance is a little underwhelming and it’s a bit fragile. And the front brake is dreadful. Grab a handful of lever, and you get the sensation of slowing down.

That being said, I find this bike interesting. That’s why I bought it. At any gathering of motorcycles, it’s almost always the only one there. I installed an electronic ignition and it was always easy to start and fairly dependable. So that makes it fun for tooling around the campground or rally site. Around the neighborhood and at the few and far between events are about the only time I ride any of my bikes anymore.

So I have decided to mount Norton forks and the front wheel from my Commando on it. But this will be a budget build. And the budget will be $0. I want to sell off the Matchless front wheel, fender, and forks to cover the cost of the pieces for the Norton forks that I don’t have. After all, AMC did it with the N15 and G15. If that lot can figure out how, I should be able to also. Give me something to do in my old age.

Research on this forum and links posted here has informed me aplenty about Roadholder forks. I found this on the forum about the G15 and N15 hybrids:

“All these machines used a new frame similar to the G.12 C.S. duplex type with bolt on rear subframe but were fitted with a redesigned malleable steel headstock machined to accept Norton forks and front wheel.”

What will be needed to adapt the Atlas yokes to the neck will be unknown until I remove the forks from the Matchless. This required some planning because the bike will be impossible to move around with no forks. And once the deed is done, it shan’t be undone and the bike could sit like that for an extended time as my interest ebbs and flows. I have now moved it to a suitable place and am prepped for surgery.

Here is what I have from my Commando:

Wheel/brake
Lower sliders
Bushings and seals
Axle

I will probably purchase stanchions and dampers new. So I believe I have a choice of G15 or Commando components. Here’s what I can think of that I need:

Atlas 7-3/8” yokes – bought for $125
Stanchions
Bearing nut, 26tpi
Crown nut, 26tpi
Springs
Dampers
Stanchion top nuts
Stanchion top nut washers
Bottom bolts
Drain screws
Sealing washers
Seal retainers
Dust scrapers
Neck Bearings


I have taken some crude measurements of the Matchless and the Commando. Measurements were taken with each bike on both wheels unloaded.
They are as follows:

Matchless

Rake – 26 deg
Offset – 2-5/8”
Axle C/L to top of neck – 27-5/16”
Neck length – 6-1/4”
Top of neck to top of stanchion -1-1/8”


Norton Commando:

Rake – 27 deg
Offset – 1-7/8”
Axle C/L to top of neck – 26-1/2”
Neck length – 6-3/8”
Top of neck to top of stanchion -1-7/8”



Here she is in her non-standard glory before surgery
[Linked Image]


Here is what I have. Saw a brake assembly sell on Ebay a couple of days ago for $230.
[Linked Image]

[Linked Image]

[Linked Image]

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knuckle head
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The change in yoke offset should/will make the steering slower...


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
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So the important measurement is the distance from axle centerline to the top of neck:

Matchless G12 - 27-5/16"

Norton Commando - 26-1/2"

Stock G15 stanchion length is 24.93". Stock Commando stanchion length is 23.15". I am unsure why there is an additional 1-3/4". But there were many other variables in the stock configurations. AN Norton lists the same spring for both sets of forks. From what research I have done, the G12CSR came with a 19" diameter rear rim. Mine is an 18".

Commando stanchions are cheaper than G15. Commando parts are more readily available. I have just purchased most of the used hardware I will need from a fellow forum member. Internals are Commando. I will still need stanchions, seals, and gasket (fiber) washers.

Cost so far:
Atlas Yokes - $125
Rubber dust scrapers - $11
Used Hardware - $140

Total so far - $277

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The used hardware arrived and 1 of the damper rods was an earlier Roadholder with CEI threads. The other was Commando UNF, but was slightly bent. Both included valve ends. Straightened the rod. Searched the internet for part number 06-0346 and found used ones at Baxter Cycle for $5 each. Called and ordered 2.

Bought new Stanchions off Ebay for $90.

Dust boots, stanchion top nut washers, and stanchions are new, everything else is used, including fiber washers and seals. I installed new seals on the Deerslayer when I changed the front forks and I will recycle the old ones. The old seals had maybe 1200 miles on them. One wept slightly, but I didn't have the paper gasket under the seals. I still don't have the gaskets either. I think I will use a smear of Gasgacinch on the outer diameter of the seals. I hope to never take them apart again.

[Linked Image]

[Linked Image]

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I have removed the forks from the Matchless. Inspecting the neck and bearings shows me that I can make the Atlas yokes fit by making two radial adaptors for the neck bearing races. Essentially a glorious washer (.300" thick) with tight tolerances on the ID and OD. This part needs to have a press fit on the ID onto the smaller Atlas stem, and on the OD into the center of the neck races. The upper race needs to have a sliding fit with bearing adjustment nut. The neck and the neck races will be reused as is. The races just drop into the neck. They have a large corner radius. I'm not sure why they won't turn in the neck. In fact it appears that they have in the past. Even though the Atlas stem is shorter, the Matchless upper yoke is much deeper as shown in the photos.

Bought a new aluminum fender. Made by Speedwell in the UK. $104 including shipping. Running total of $490 I think. Will need to make a new instrument mount. Still need to pay my friend to machine the parts. He doesn't usually charge me too much though. Great to have a friend like that.

The entire Matchless front assembly is listed in the garage sale forum. Should be almost identical to a P11 Norton as well. It will be interesting to see what the value is.

[Linked Image]

Races will be reused. ID must be reduced. Balls are 3/16".

[Linked Image]

Matchless top yoke is significantly taller.

[Linked Image]

Top of the neck. Fixed distance between original races. They just drop into the tea cup.

[Linked Image]

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A friend who has a machine shop made me bushings (spacers?) to reduce the inside diameter of the bearing races which install on the fork stem. The lower one was tricky because it needed to be a light interference fit on both the ID and OD. The upper has a slip fit for the nut on the ID. He made them to fit into the race and then turned the ID to the required diameter. Each required a different OD. The goal was .0005"-.0010" interference. I didn't measure, but I drove the assembled race onto the stem and I think the fit there seemed right. Very nice for $50. He felt a little bad that it was so much, but I don't think it was. He's using his machines and tooling along with his time. He said his brother spent 1-1/2 hours on it. He said doing something on the Manual lathe had a re-learning curve for them, because they do it so little anymore. I'm just glad I can still find someone willing to do it. Over the years, I have made parts using a lathe and milling machine. I would have spent all day and to make 4 or 5 that wouldn't have fit right.

The stem is coming up short for an original nut that I have. A new nut will have to be made which will have 3/8" more reach. The new nut will have about the same thread engagement as the stock Atlas one. I ordered a 5" long piece of 1-5/16' hex stock of 316 stainless steel. $27 + $15 shipping from On Line Metals. Running total of $530 for this fork conversion. I still will need to pay for the nut to be made.

I will also have to fabricate stops to limit fork rotation to stop from denting the tank. The Matchless yoke had extended pinch bolts which butted to the frame for this. The Atlas lower yoke also has a large flat area where I can attach a stop by welding. Still to be designed. I really should also make a shroud for the upper bearing. The gap between the races is exposed for all to see and enter. Maybe later.

[Linked Image]

[Linked Image]

[Linked Image]

Only 7/8" of space here, the machined surfaces of the upper yoke are 1-1/4" apart here.

[Linked Image]

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