1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Racing monoshock frame

Discussion in 'Norton Commando Motorcycles (Classic)' started by jseng1, Mar 13, 2020.

  1. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    Just got this photo of a JS monoshock frame being built by Mark. This is only the 2nd one I know of so far.

    [​IMG]
     
    fiatfan and grandpaul like this.
  2. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    Very nice indeed!
     
  3. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    Usually you find that when you make something as nice as that, the rules for most race classes preclude it's use. In Australia, the only development classes are historic and the rules are very stringent. A better approach might be to define engine type and capacity and make the rest open slather. If I was racing and somebody came along with that frame fitted with a Commando engine, I would happily race against them. All this stuff about tyre sizes, fuel type, suspension and frame mods is bullshit. If you don't fit a very different motor, you will never have any real advantage.
     
    illf8ed likes this.
  4. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    When you build a frame such as that, it is only a starting point. Getting it to handle competitively is something else, even though the theory might be excellent. If you have got it wrong, it might grab you by the throat.

     
    Last edited: Mar 13, 2020
  5. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    My Seeley 850 handles extremely well, but that has only happened through sheer arse and perseverance. My other project is a monoshock Egli frame with a 600cc two stroke engine which is based upon an H1 Kawasaki engine. It has RG250 forks and 17 inch wheels. I have been able to retain the 25.5 degree rake of the RG250. The bike is unlikely to ever run, but if it does I will need to be extremely careful when testing it. There are many more ways of getting it wrong than there are of getting it right.
     
    Last edited: Mar 13, 2020
  6. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    This is not a new development. It is a copy of Jim's original design, which was well proven with very good results in twins class racing in the US. With a 3rd place in its class at the AMA Nationals at Willow Springs in 1990, it was the last Norton to be on the podium in an AMA National event. Pictures below from Biker's Station magazine coverage of the 1990 Daytona race.

    Page 0 1200.jpg

    Page 2 1200.jpg

    And a shot of the happy team at the Willow Springs National. I'm the one with the fine moustache:D.

    Ken Rob Denise Trophy 2 1200.jpg

    Ken
     
    elefantrider, Fullauto, willh and 2 others like this.
  7. Craig

    Craig VIP MEMBER

    Joined:
    Dec 20, 2005
    Jeesh Ken , very good looking team you were part of , good on you ! Nice looking race machine as well !
     
  8. 850commando

    850commando

    Joined:
    Nov 1, 2014
    I like it, i just don't have the fabricator background to build it. looks like the engine is solid mounted. is the cradle floating or part of the chassis?
     
  9. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I like the bike, I just regret that our race rules in Australia discourage that sort of development. I love it when the guys do something different - trick frames are usually excellent. A friend of mine has made a few. Some of them get raced when their owners make false claims about what they are. But that's OK, the development is worth pursuing for it's own sake. Some people believe I am a purist about historic racing when in reality I would prefer it did not exist. If we are going to do historic racing, let Goodwood Revival and Landsdowne Series set the pace - otherwise we should get rid of as many rules as possible.
     
  10. edgefinder

    edgefinder

    Joined:
    Aug 28, 2012
    Rob Tuluie went to school in Austin a couple years around that time. He did 1.29's his first time at my home track Hallett the same day I broke 1.30 him with drum brakes me on a 600 hurricane. He was the first guy to tell me get the Norton don't bother with the other brit bikes. Wish I had a picture of his bike
     
  11. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    You mean this one?

    Rob with bike 1200.jpg

    Left Side.jpg

    This is the same bike in race trim at Daytona in 1990

    Nortons in Line 1 1200.jpg

    Ken
     
    Last edited: Mar 13, 2020
  12. cjandme

    cjandme

    Joined:
    Feb 5, 2011
    Dang.......check out that fire cracker (black cat) :0)) nice intake ....bet it breathes!
     
  13. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    In my opinion, the best road-race fun you can have - is to build your own bike and have a bit of competition success with it. For me, it is what motorcycling it is all about. As far as my Seeley 850 is concerned, I have done what I set out to do - I got ahead of the pack - once is enough. I turned under the fastest in Period 4 at turn two and they were behind me. Anything else does not matter much because the rest is easy. Back in about 2003, I won a couple of races at an old farts meeting - it did not mean much. Period 4 Historic is a bit more serious - what is in it is as good as a quick Z900 Kawasaki.
     
  14. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I wonder if the next lot of road-racers will be developing their own bikes ? To me racing a modern bike would be like owning a nice ping-pong bat.
     
  15. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    Yes its a solid frame and swingarm. It needs the lightweight pistons and longer rods for reduced vibration. The 1st lightweight Norton pistons from Wiseco were run with this frame at Willow springs, Sears point and Laguna Seca around 1988.

    Weight was approx 320lbs with 1/2 tank of gas
     
    Last edited: Mar 14, 2020
  16. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    What is the AMA race class in which monoshock Nortons compete ? From the little I know about the AMA, with their classic racing rules they are very hot on cheaters. Personally I don't really care who cheats in any way as long as it does not involve over-capacity motors. If I was racing and somebody fronted with a monoshock Norton, I would be happy to race against them. A lot of these developments help the rider more psychologically than in fact.
     
  17. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Back when we were racing the bike, AMA had several Battle of the Twins classes, later to become Pro Twins classes, but AMA gave up on them, and they were absorbed by AHRMA, the America Historic Racing Motorcycle Association. That's where the bike would fit if it were being raced today.

    Ken
     
  18. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    An early version of that bike when I was riding it - before Ken tricked it out with mag wheels and 920cc.
    [​IMG]


    The shortened cylinders and 850 Wiseco pistons I ran in the early version
    [​IMG]

    Powering out of turn 2 at Willow springs in the late 1980s with a 4 cylinder jap bike on my ass.
    [​IMG][​IMG]
     
    Last edited: Mar 17, 2020
    Doug MacRae likes this.
  19. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    It was AHRMA I was thinking of - not AMA. When historic racing began in Australia, that is when I walked away and did not go back for 25 years. When I raced, it was always in an open class, even though I always raced an old motorcycle. With historic racing, the approach is always negative. The first thing the rule-makers do is think about what the DO NOT want competing in historic events. It is never about trying to get full race grids. So the costs of racing are always higher.
    I am never a purist about racing, highly developed motorcycles always interest me, especially when a privateer does it. If we are going to do historic racing, there should be no bullshit - I thing Goodwood Revival is good like that. But my preference is always to race in an open class based on engine capacity and machine type. If I race a two-stroke, it needs to be in a two-stroke class. And a four-stroke in a four-stroke class. Mixing the two is a waste of good race machinery. Any other rules are pretty much superfluous. I don't care if the guys run nitro.
     
  20. Blewdy Yaink

    Blewdy Yaink

    Joined:
    Nov 10, 2018
    I love this thread.
     

Share This Page