Matchless G80CS Frame Suitable for Road Use?

I have had a 1961 Matchless G80CS for 40 years with ideas of converting it from desert trim to mild cafe trim at some point. For a long time I thought something like a featherbed frame might be just the ticket, but now I'm thinking that the existing scrambler frame might not be so bad if it were repaired and modified with things like Commando forks. What differences were there between the scrambler & roadgoing G80 frames? The existing frame might be heavy but is it otherwise suitable?

Paul, SoCal

The British motorcycle industry has a long history of competing in trials and enduro events, going back to the dawn of motorcycling. AMC (AJS and Matchless) were a big part of this from the 1930s onwards (AJS from 1920s onwards) - the brochures generally show a 'competition' or trials version, and the ISDT events (International Six Day Trials) were largely speed based . AMC had one of the biggest competition shops in the business, competing with BSA Goldstars etc in all their formats. And in the 1930s, almost every factory produced a bike like this for their catalog = scramblers with lights, but road geared.

So a road based CS bike would not be out of character at all, and the CS has the ponies to keep ahead of the trafffic if required. Much more fun than the road bike offerings ?

Pic is recent, Mick Andrews meeting up with his old 1966 ISDT bike - the very last of the AMC big bangers, although the scrambles bikes as Matchless's went for a few more years yet....
http://www.trialmag.net/news/11/3085g.jpg
Note the registration plates.

P.S. Maybe a G80CS roadgoing pic would be more suitable.
http://www.vintagebike.co.uk/pictures/w ... 60x570.jpg

Have fun, hope to see what you end up with...

Thanks Rohan, your second picture is close to what this G80CS looked like when new. When I bought it back in 1971 or so, it had been an old desert racer that had been converted to a chopper with an extended front end, peanut tank and solid bars replacing the rear suspension units. It did come with a box of parts including the shocks, original tank, headlight, seat & tubular tool box. I rode it home, got stopped by the cops who were most unimpressed with this outfit - and tore the chopper bits off and reinstalled the desert bits. We used a plastic dirt bike tank that we got someplace as the original gas tank was suspect. I rode it this way out in the California desert for some years until work took me on the road out of the area. The Matchless has been sitting ever since waiting for me to do something with it.

I bought a chopper but saw a cafe job in my mind's eye. Over the years, I thought it might be best to restore it to original condition and have collected some of the missing parts. I was never able to work up any enthusiasm for the restoration and the project has not moved forward at all. Recently I saw these pictures:

http://www.britcycle.com/Bikes/matchless_cafe_racer.htm

This really inspired me to look into this again as this was just what I had envisioned all those years ago. As I recall, the Matchless had a reasonable amount of power delivered in an easily controllable broad curve. This ought to lend itself to a fun sporty weekender, one that would suit my tastes these days seeing I no longer care if I get passed in the twisties. Seeing my tastes are more modest now, maybe the stock frame might be fine after all.

What I was unsure of was how well the old scrambler frame would suit fast(er) road work. Would it steer OK, not too fast to be stable? It seemed fine in the dirt but this was at very low speeds compared to road speeds. What of the gearing? What sort of speeds will the stock gearing provide? Is a 65 mph cruise practical?

Paul

Don't know - try it and tell us !!

The CS was quite a capable road bike for its time, but if you are intending to go canyon carving at racing speeds, the first thing you are likely to find is that you need more front brake ?. As for all the extra bling... ???

P.S. Someone here has a CS that they bring out on regular road runs. Appears to be quite a good road bike, more than capable of a good turn of speed.
In the ISDT tests of the time, in which AMC factory riders always did well, I seem to recall they were well capable of 100+ mph. Gold Star territory, in fact....

Cheers.

Well, 100 mph is well in excess of the sort of speeds I had in mind. "Canyon carving at racing speeds" also seems a bit grandiose for what I had in mind. I'm old enough to think of the pain involved in crashing and that should act as a brake on my enthusiasm . . .

Just the same a brisk fun pace might be a good goal for this old Matchless. What did you mean by extra bling? I had in mind something minimalist with no more gear than the bike would have come with when it was new.

Paul

hudson29 said:

Just the same a brisk fun pace might be a good goal for this old Matchless. What did you mean by extra bling? I had in mind something minimalist with no more gear than the bike would have come with when it was new.

Paul

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Well, that featherbed framed cafe racer you linked to has all the bling.
Manx looking bling at that.

I'm sure a Matchless could be done as a cafe racer without discarding 90% of it, and still do what you want. For road work these days a stronger front brake is probably high on the first-to-do list ? The rest is optional...

Can we point you more towards a G50 looking cafe racer - at least keep it looking more like a Matchless ? (Not trying to influence you here !)

We look forward to seeing and hearing of it.

Rohan said:

Can we point you more towards a G50 looking cafe racer - at least keep it looking more like a Matchless ? (Not trying to influence you here !)

Click to expand...

You are reading my mind! While the Manx looking featherbed framed custom was the inspiration that got me thinking about this project in current terms, the G50 is the guiding star. Being able to use the existing frame would be a huge leg up as it is already on hand and looks something like the G50 frame. If the factory riders were able to take the scrambler models to 100 mph there is some hope that it might be suitable for a fun weekender. A complete early Commando front end would upgrade the brakes and keep the project all in the family. I'm unsure about the technical aspects of this combination, but it probably isn't rocket science.

Has anyone done anything like this in the past?

Paul

hudson29 said:

Has anyone done anything like this in the past?

Click to expand...

Undoubtedly.
Nothing to stop you doing your version of a CS cafe racer though, should go well.
That all alloy engine already marks it as something special in the brit bike world.

A quite elderly gent near me has a little *onda dressed up as a G50, with the tank and paint, clipons, racing seat and semi-megaphone. Did a doubletake first time I saw it out-and-about, looked like he was having fun....

Look forward to seeing what you come up with...

I just bought a little Honda much as you describe. It is a 1990 Honda GB500. I lucked into finding it while looking for a Suzuki VX800. The same fellow had both bikes and we made a package deal. I love the little GB500, it is powerful, smooth and even has an electric leg but it is not a real Matchless. The Matchless project will never have the level of sophistication the Honda has but it can be made to be just what I think it ought to be. That is a worthwhile goal on its own.

Paul

Looks tempting to put Velocette badges on that bike.
Hush my mouth, what am I saying...

If Velo were still going, would they be building something like that.... ?

Yes, that is tempting. When the bike came out more than twenty years ago, the magazines made much of the GB500 looking like a BSA. I can't see it. You are right, a Velo is closer to the mark. They might have made this themselves.

I think we tend to see something of what we love in the newer bikes. I bought a 1978 Yamaha SR500 from one of my Hudson cronies many years ago. Later on, I found we both called it the same thing - the Japanese Matchless!



I could see this bike with a big flying M on the tank. If AMC were still around in 1978, they might have made a bike much like this one.

When I first rode the 1991 Suzuki VX800 it struck me that this was the big prewar Matchless V-twin updated. It had the same sort of mechanical feel I was used to in the old British bikes, not the soulless electric motor feel some J-bikes have.



Another flying M on the tank? I dunno . . .

Paul

Those spoked mag wheels reminded everyone of the Arter Matchless ?
When the SR500 was new, an Australian bike magazine tested one against a 50s G80 Matchless. The Matchy actually came out pretty well, considering it was 20 years older and a 30/40 years older design.

In Japan, the hop-up crowd apparently offered fake bolt-on gold G50 cam-chain covers to fit the SR500....

Interesting, I've got one of those VX's too, stiff legged feet forward just didn't do it for me.
It was nearly less expensive than a leccy starter for a Commando - feels a lot heavier than a Commando though. Was waiting for Yam to bring out a bigger version of the SRV250.

Mmm, think British !

Rohan said:

Those spoked mag wheels reminded everyone of the Arter Matchless ?
When the SR500 was new, an Australian bike magazine tested one against a 50s G80 Matchless. The Matchy actually came out pretty well, considering it was 20 years older and a 30/40 years older design.

Interesting, I've got one of those VX's too, stiff legged feet forward just didn't do it for me.
It was nearly less expensive than a leccy starter for a Commando - feels a lot heavier than a Commando though. Was waiting for Yam to bring out a bigger version of the SRV250.

Mmm, think British !

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I would love to read that comparo between the old Matchless & the new SR500. Do you have a copy somewhere you could scan?

You have a VX800 also? These are pretty rare and mostly unknown motorbikes. I'm not really sure why, but they just didn't sell well. I declined to purchase one new as I thought them too expensive & complicated. Having seen how well they run these past twenty years I had to admit I was wrong and go find one. I think they may have only been made for four years. They are heavy, something like 90 lbs more than the Commando. Once moving the heft isn't an issue but if you have to push it any distance . . .

Mine is a clean low milage example and needs only to have the carbs cleaned and synched. It sufferers from the low speed stumbles now. I still love it and will keep riding it until the SR500 & Norton are both out of the workshop & back on the road again.

What part of the world are you in Rohan?

I'll work on the magazine test - finding it will be the issue.

Those VX's are more common than you think - they were sold though as the UJM (Ultimate Japanese Motorcycle) and were rather low key compared to the performance fours. High mileage examples have the charming habit of putting rods through cases, so spares are plentiful and cheap over your way - here in Oz the supplies seem to be drying up.

Cheers.

Rohan said:

I'll work on the magazine test - finding it will be the issue.

Those VX's are more common than you think - they were sold though as the UJM (Ultimate Japanese Motorcycle) and were rather low key compared to the performance fours. High mileage examples have the charming habit of putting rods through cases, so spares are plentiful and cheap over your way - here in Oz the supplies seem to be drying up.

Click to expand...

If you find any sort of magazine writeup on the G80CS I would love to have a scan. I really know little more about it than I can determine from seeing it and having ridden it in the dirt - 40 years ago. Someone said it weighed in at 360 lbs. stripped down for the desert. Gulp! If this is true it will have the heft of a 650cc Triumph without the power. Hopefully it will compensate with charm, dignity & presence for what it lacks in speed.

We have a lot of folks from AU on the VX800 Forum, one who has added a Matchless flying M to his instrument cluster, a kindred spirit in WA. Perhaps the VX is better known elsewhere. In the limited experience I have with it amounting to two local bike nights, no one seemed to know what it was. It did attract some favorable attention, much to my surprise.

Parts do seem to be cheap & plentiful on ebay, too bad it is from destroyed motors. Happily this must happen only at very advanced mileages as many VXs seem to have quite a few on the old clock.

There is certainly a lot to be said for using a featherbed frame on this project. The featherbed is a known quantity having been the focus of spirited customs for more than half a decade. Just on this forum there are any number of threads dealing with these projects. Bolt on parts are available from several suppliers. I'm no fabricator and this really appeals to me. There would be a big job in designing and making up the plates to mate the engine/trans unit to the frame but that is the worst of it. Pretty much everything else can be sourced off the shelf. This would probably be the easier and surer project path, but it could well be the most expensive one as well.

The existing frame is the real unknown. I can find very little information and can only guess it might work out OK for this café funster project. The motor plates are there and can be used with clean up and paint but everything else will have to be a one off fabrication for this project.

The condition of the stock frame is also unknown. I do know it has some visible damage which will require that a length of tubing needs to be replaced. Stripping and inspection by an expert will be needed to see how much work will be needed to use it.

There are several projects ahead of this one on the priorities list but it is fun to think about and figure out which path to take.

You can always build it up with the existing frame, and transfer everything to a featherbed if that is the way you decide to go. And keep your Matchless a Matchless in the meantime.

But again, these bikes were good for 100+ mph in enduro / ISDT / desert events back then, if they weren't any good they wouldn't have sold a zillion.

BTW, interesting Matchy for sale in NZ, rather along these lines.
50 years of development, from rigid bike to sprung Roadracer.
The forerunner of the postwar 7R.
Not much 1947 left though.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0609942164
But he doesn't say how it races.
38 hp was a lot for a 350cc in 1947....

I found a very interesting article from Cycle World, April 1962. It is a roadtest of a Matchless G50CSR, a machine I had not heard of that takes the roadracing G50 engine and puts in in the chassis of the G8CS scrambler. They say the chassis is the same as the ones used in the other large scramblers. The G50CSR was equipped with trials universal tires and the magazine reported the observed top speed to be 122 mph. Someone with large brass attachments had to ride this bike at speed with those tires. They further went on to say that with good rubber the Matchless scrambler would "roadrace with the best of them."

While this claim might seem fanciful, it does indicate that maybe this old dirt bike might not make so bad a cafe funster after all. The beast is still heavy though, 385 lbs., the G50 motor saved no weight at all . . .

Here is the article:

http://archives.jampot.dk/Editorial/Roa ... ril_19.pdf

Weren't they built to homologate something for racing in the USA ?
Someone in the UK was building something along those lines in replicas for wealthy japanese collectors a while back, recent-ish though.
You'd imagine those speeds are calculated, trials universal tyres back then just aren't rated for those sort of speeds. Even good racing rubber was barely up to it.
An engine with that sort of horsepower isn't going to be lighter, needs some serious strength to make those ponies. !

So, we are finally realising the CS was a very good bike in its day too, up in GoldStar territory in fact !! AMC had a very big competitions dept, sold a lot of CS compy bikes, and had some of the best riders, so you'd expect this....

I have not read anything about the homologate issues with the G50CSR, but this certainly could be the case. The bike had no ignition retard or exhaust valve lifter making it tougher to start as Cycle world duly noted. I too have some skepticism about riding 122 mph on trials tires but the text indicates that they did just that. In 1963, the same magazine tested the G80CS with knobbies and made no attempt to determine top speed, a fact noted in the text:

http://archives.jampot.dk/Editorial/Scr ... _July_1963).pdf

The magazine writers estimated the practical top speed to be 90 mph. What all means to me is only that the existing scrambler frame might be fine on the road for lively Sunday outings.

I have never ridden a Gold Star but have often heard they were something special. To think of them in the same league is pretty high phrase. I was talking over the weekend to Keith Moore, my local friendly Triumph parts & wisdom dispenser. Keith goes way back with these bikes, back to when they were new. He says the Matchies were always well built but heavy as hell. It really would be fun to put the G80CS on a diet with the featherbed frame, and all of the rest of the trick (bling?) gear. I wonder what it could be got down to? Right now, this project is looking to weigh in at its full 380 lbs or something somewhat less depending on battery replacements and other gear.