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Matchless G80CS Frame Suitable for Road Use?

Discussion in 'AJS & Matchless' started by hudson29, May 18, 2011.

  1. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    How much weight do you expect to save with a featherbed frame - 10 lbs ?, if its lightweight tubing ? And then have to discard all the Matchless cycleparts - including the teledraulic forks with their prized hydraulic control and hi-tensile fork tubes...

    38 bhp out of that Matchless 1947 Cadwell 350cc engine was more hp than a 500cc Goldstar engine put out, for some years to come. So the CS engines had some pretty illustrious ancestors... (although it was on 'dope' ?).
     
  2. gtsun

    gtsun VIP MEMBER

    Joined:
    Sep 21, 2009
    Hey Paul, Glenn here. To get an idea how the G80 could work in cafe trim you should go to the wonderful web site of OldBritts.com (Fred & Ella's) parts place. Go to the home page, scroll down & click on "bike articles" scroll up & click on "featured bike" by Les Cook. It's a story on his Norton P11 road racer and it's a pretty tough & fast looking bike. The P11 was a scramblers bike with a Norton 750 Atlas type motor and a Matchles frame. Matchles had their own version too, look at that poster in your garage, I'm sure you have a picture of one. Anyway, I think when you see the Les Cook bike in Old Britts web site you'll get the picture. I'll help, let's get it started but the Norton's rear wheel first. This week end? Oh, don't forget the Sunday Vintage bike gig in Huntington Beach at 2:00 to 4:00pm. Glenn.
     
  3. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    Is that all, 10 lbs difference? I could lose that much by eating a smaller lunch over the course of a month. I had expected more like 30 lbs . . .

    I'm starting to see a trend here. In my own small collection, the Matchie, the Triumph, the SR500 & the GB500 all weigh about the same - 390 lbs gassed and ready to go. What would a Goldie or a Norton featherbed single weigh? Are we in the same ballpark?

    Are the Matchless forks worth retaining over something like a set of Atlas Roadholders? If so, will a Commando TLS brake fit them? The Teledralics are there and might be in good shape. They took a beating in their first 15 years so they would have to be looked at.

    I have found only one reference to the output of the G80CS motor. One of the magazines reported 33 hp. I imagine that figure was probably supplied by the distributor and may be suspect. If it is true, the Matchie ought to perform something like the SR500 with the same power & weight. That's more than acceptable in my book.
     
  4. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    That is some build. Les is actually using a very rare G85 frame. That was a lightweight version made just for scrambles. He has a lot of other gear on it including different triple clamps & a Commando front end. I had something more modest in mind . . .

    I have started on the Norton already by getting at it and cleaning a dozen years of filth. It is looking pretty sharp now! This weekend the long delayed work will start in earnest by measuring things up looking for the speed wobble and then tearing into the rear hub maladies.

    We'll see about the Vintage Bike show. If I'm getting things done on the Norton it may be better to keep at it.
     
  5. batrider

    batrider

    Joined:
    Aug 9, 2008
    My '66 G80CS is fine on the road. Many of these came to the states with full street gear. The lights were quick disconnect so you could ride to an event, remove lights, muffler, etc and go racing.

    Mine has the stock gearing (5.8:1) and with stock muffler and jetting it goes about 80-85 mph top end. Following the manual recommendations I once removed the muffler and rejetted the carb with a huge main jet - something like a 300. (Edit: was a 330) The difference was night and day. I had it to 99 mph indicated with my chest on the tank. No tach so I just kept on 'til it wouldn't go any faster. Scared the heck out of a farmer checking his mailbox though. It was loud but sounded beautiful.

    Read the manual for specs - from Christian's Archives: http://archives.jampot.dk/Book/Owners_m ... 1_1967.pdf

    Handling is equal to my Norton with DT head steady (very good). So I think you will have no problem building a sweet cafe out of a G80CS. Even a stock G80 road bike is pretty quick and handles well.

    Russ
     
  6. dave M

    dave M

    Joined:
    Oct 19, 2005
    Hudson, I wont say that a Norton Featherbed is over-rated, but I will state that in my opinion many other frames are under-rated. The ubiquity of Featherbed-framed specials had more to do with their availability than almost any other feature. The Manx engine was a very competitive unit in single-seater-open wheeled car racing circles, however Norton would only sell complete machines. The car guys bought a Manx, took the engine and sold the rest on for whatever they could get. BSAs were always respected for their handling and there are a decent number of specials using these frames. Early Norton engines like the original iron-head Dominator and the push rod singles were rather slow, but housed in a fine frame, early Triumph Bonnevilles with bolt-up frames were fast but rather flexible, particularly when owners discarded the fuel tank (which was designed to impart additional rigidity to the upper frame) in favour of a fibreglass unit. By the mid 60s Norton's 650SS was as quick as anything on the street in that class and the Triumph Bonneville had a new frame that handled very well indeed. So in a nutshell to all intents and purposes I consider a Matchless G80CS frame to be a fine candidate for a cafe-racer special, indeed I have read that these Matchless frames are superior at taming the vibrations of a 750 Norton twin. I myself am building a G15 replica from a G80CS frame and a Commando engine.
    The last one to finish their project is a sissy!
     
  7. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    Yes, mine did as well. The original headlight & cylindrical tool box are still in a box on the shelf awaiting better days.

    Wow! Rohan said these bikes were capable of doing the ton back in their day and your experience pretty well confirms it. My own memories of riding the Matchless are clouded by my youth and inexperience and the passage of 40 years. I remember the bike being sort of gentile to ride (compared to the two stroke dirt bikes I was used to), powerful but in a controllable unspectacular way. I used to delight in doing flat track style power slides on the dry lake bed throwing out enormous rooster tails of dirt with the knobby tire. Knowing it is capable of such speeds as you attained makes me think that 80 mph might not be too much to ask for keeping up with my Norton friends. They all seem to be as speed mad as I used to be myself . . .

    Thanks for this. I see the oil recommendation changed from straight 50w to 30w. I wonder why? I used to use Castrol GP 50w, probably unavailable now. I'll bet the same 20-50 GTX I use it just about everything else will work fine.

    This is really what I was hoping to hear, the frame on hand will be fine once repaired. Equal to a Commando? That is sweet to hear as I always liked riding a Commando. Now we are down to details. Do you have any pics of the top of the engine and the headsteady? I just realized recently that the G80CS is supposed to have one, mine was gone by the time I bought it. Possibly the guy that chopperized it removed it to fit the peanut tank . . .

    Vintage Paul
     
  8. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    Thanks dave m, you give much food for thought here. First, I think we probably have a problem with historical perspective. In our modern era of motorcycle specialization is is easy to think our predecessors were specialists as well. I'll bet the designers of the frame used in our "scramblers" had no such use in mind at all. They most likely were making the best motorcycle frame they could given the level of knowledge & production techniques at hand at the moment. That the frame happened to suit the odd Americans who used motorbikes in the desert is almost certainly an accident.

    Somewhere along the line, the heavy old Matchless frame was determined to be tougher in such use than the Norton frame and the hybrids were born. I'm now pretty comfortable using the G80CS frame for my project. While the featherbed solves some issues by having lots of on the shelf kit available for it, it creates other problems of a more fundamental nature. At least I will not have to design & fabricate engine plates and worry about chain runs and such.

    What attracts you to the G15? You are certainly going to a lot of trouble to build one. Why a Commando engine rather than an Atlas? I'm just starting to think about the Matchless as an active project. The bike is still a rolling basket case right now and I'll leave it like that until more decisions are made and bits obtained. Don't look for it to be scaring old ladies any time soon!

    You don't happen to have and G80CS headsteady bits surplus to your requirements do you?

    Vintage Paul
     
  9. dave M

    dave M

    Joined:
    Oct 19, 2005
    Paul,

    The reason I am using a G80CS frame is exactly the same reason most of our motorcycling forebears used Norton, Ducati, BSA or other frames for their specials - it was available at the right price! One of my chums bought a project bike on e-bay simply because he wanted the Matchless engine to put in a Featherbed or Rickman frame. I got the rolling chassis for peanuts. As far as the choice of engine goes, I have lots of Commando spares knocking around my workshop including a complete engine, so I hope to end up with a fun project that wont stand me in too much money. I have always admired the hybrids, especially the P11s, as I consider these to be the fore-runners of the Super Motards that are so popular today. The project is not too complicated, with G15 engine plates and a suitable gearbox case which I have already acquired, the whole thing fits nicely in the g80 frame with only minor modifications. The primary drive presents some technical challenges as the Commando engine and gearbox are further apart than on the G15, but nothing too complicated

    The head steady as far as I can ascertain is simply another mounting to tame the vibrations and can easily be fabricated between any convenient mounting points on engine and frame.
     
  10. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    Fair enough, this seems to be the way most of these projects get rolling. I'll be interested to see how you get on with it. Do you have a tank, seat and other cycle parts lined up yet? How is your chum's project going? I would love to see some pictures of his build.

    If I can't find the Matchless parts, I'll see what can be cobbled up. I'll bet someone has these parts sitting around as the result of projects just like yours.

    [​IMG]

    I found this picture on the internet, unfortunately with no details at all. It looks to be a G80CS complete with the Teledraulic forks, both hubs & brakes and possibly even the scrambler fuel tank. The motor looks like it has a tuned intake tract and exhaust. Does anyone know anything about this bike? I wonder how it runs . . .

    Vintage Paul
     
  11. dave M

    dave M

    Joined:
    Oct 19, 2005
    Paul,
    I haven't got a tank for it yet, they seem to go for quite a lot of money on E-bay as they are the same tank as on the P11s which are becoming more sought after. I might go for an alloy tank from The Tank Shop, I had a 3 1/2 gallon Manx short circuit tank for my Commando cafe racer from them and I was very pleased with it. I have collected the correct oil tank, battery and tool tray and sundry other items for a G15, I will have to reweld the mounting brackets for these, but other then that there doesn't seem much more in the way of frame mods. I will also have to alter the engine balance factor of the Commando engine to accommodate the rigid mounting. I am slowly collecting the parts I need as I am currently in the middle of restoring 2 more Commandos - one Dunstall equipped cafe racer and one Roadster, a 1965 Triumph Bonneville and a 1927 BSA flat-tank 500, so I have enough on my plate for the moment.

    My chum with the G80CS engine is also encumbered with a plethora of projects and hasn't really got round to his cafe racer special yet. I have to say that the photo of the Matchless you posted looks great and I bet it would be a lot of fun to ride.

    If you do a topic search using 'Commando engine into a P11 rolling chassis' you will see among other things a link to an article and some photos of a bike built by Ludwig, who was a regular contributor to this forum until recently when he hit 1000 postings and decided to retire, Ludwig has built a wonderful beast with a Commando engine, front end and shortened primary drive into a G15 frame, I hope to achieve at least somewhere near the quality of what he has done.

    Warmest Regards

    Dave
     
  12. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    [​IMG]

    This gives me an idea. From what I can see here, the P11 tank might fit right on the G80CS frame? If so then The Tank Shop already has the mounting pattern needed to make a G50 tank to fit the G80Cs frame. There would be other things to work out of course but there is a possibility anyway.

    Wow, your workload is a long one. I have only three motorbike projects in the hopper now but several car & truck projects in the mix too. It will take several lifetimes at the rate I complete things . . .
     
  13. Rohan

    Rohan

    Joined:
    Aug 26, 2010
  14. hudson29

    hudson29

    Joined:
    Feb 3, 2011
    Yes, there are a lot of SR500s done up like the great British racing singles. There is an outfit with the unlikely name of Custom House Stinky in Japan that specializes in such conversions. I can see how this would work, I bought my SR500 because it was so much like a modern Matchless. I even have a Matchless key fob for it.

    [​IMG]

    I have been giving the Matchless a great deal of thought and have even moved forward with getting another front end and brake that will look period but improve braking performance. I found an entire front end from a 1972 Suzuki GT750 that has a 4LS brake, or possibly it would be more accurate to say a dual TLS brake, one on each side:

    LHS
    [​IMG]

    RHS
    [​IMG]

    This is going to look really good on the old Matchie! I'll have to see if it will polish up, if not black paint works too.

    Vintage Paul
     

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