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Commando Top Speed? (2010)

Discussion in 'Norton Commando Motorcycles (Classic)' started by highdesert, Dec 21, 2010.

  1. Seeley920

    Seeley920

    Joined:
    Jan 6, 2009
    I have seen Steve Maneys bikes in action many times...I race against him. Yes they are fast....very fast!! 100crank BHP....probably close, I've seen him beating TZ750s and his 1007 is one of the quickest bikes I've ever seen at Snetterton, which has quite long straights.

    I've already quoted the gearing and revs that my bike pulls easily...Steves 1007 will pull a lot more than that!
     
  2. pommie john

    pommie john

    Joined:
    Nov 18, 2005


    According to my gearing spreadsheet your Seeley is pulling 145mph at the stated rpm ( 7800) I made an assumption that that tyre is roughly 80" in circumference.
     
  3. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Some years back one of Steve's 920 engines delivered 87.9 horespower at the rear wheel on the Hobbsport Dynojet dyno. That equates to over 100 horsepower at the crankshaft. I wouldn't be surprised if the 1007 is over 90 at the rear wheel.

    Ken
     
  4. Carbonfibre

    Carbonfibre

    Joined:
    Nov 16, 2010

    If thats the case Steve Maney should be easily be able to get work with any top FI or drag race team! Anyone able to get 100BHP per litre from a 1940s based pushrod twin cylinder motor, has the type of skill which which the top teams will pay dearly for.
     
  5. Rohan

    Rohan

    Joined:
    Aug 26, 2010

    Well, actually, when you look into it, Nascar engines are an ohv pushrod design, and they get ~750 hp (or more ?) from a 5 litre engine, @ 9500 rpm. Thats 150 bhp/litre. And bigger pistons than a Norton. And a few more revs.

    So perhaps the question should be why Nortons, as good as they currently are, are so far behind. ?

    And F1 engines are currently getting ~300 bhp/litre, at twice those revs, so are all these skills so specialized they are totally non-transferable ??

    Food for thought, anyway....
     
  6. cash

    cash

    Joined:
    Nov 10, 2006
    .

    I would say;

    Piston speed and crank support.

    Cash
     
  7. Seeley920

    Seeley920

    Joined:
    Jan 6, 2009
    100bhp per litre was surpassed a long time ago....my 750 commando (I don't have a 920!) makes 70 at the wheel!!
     
  8. Seeley920

    Seeley920

    Joined:
    Jan 6, 2009

    Thanks John, that sounds about right....I was running with a pair of 930 triples at the time (although Cormac was long gone by then ;-)
     
  9. pommie john

    pommie john

    Joined:
    Nov 18, 2005
    OK. I've added a few more data points to the graph. They are again, all tested figures from various magazines, rather than manufacturers claims.
    The trend of horsepower to speed is very clear. However I've also plotted in red three claims we've had here: The Guzzi running 187mph at MIRA, the JPN running 170 at a French airfield and The JPN at Daytona at 155mph. I've assumed 75 BHP for the Norton which is probably generous.

    In my opinion, when something strays too far from a trend, you have to ask questions about its validity.

    The Guzzi had a dustbin fairing which was very efficient, but the figures just don't look right to me.

    The 1972 JPN had a full fairing, but not the wind tunnel designed Peter Williams one. I simply cannot believe it would do 170mph.
    The 155 at Daytona is a bit off the trend, but maybe possible.

    [​IMG]
     
  10. Carbonfibre

    Carbonfibre

    Joined:
    Nov 16, 2010
    If you can go 170mph with 70bhp at the rear wheel, then what sort of speed is more modern bike, with double the power and less weight going to achieve?
     
  11. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    The answer to that is that fairings and full fairings and total enclosure fairings are the stuff of world speed records, and aerodynamics is a science to itself, so all this needs to be considered.

    A lot of modern machinery is very wide and porky, not good in the aerodynamic stakes.
    Put it in a streamliner, and consult the Bonneville lists....

    NSU held one (of many) world speed records in 1956, a 500cc streamliner did 211 mph from 110 hp ( Full enclosure of course, but the Guzzi V8 doing 187 mph is similar in concept.
    Where does that plot out on pommie johns chart....?
    There are many such similar examples, they would start their own trend lines ?

    P.S. Where did this JPN doing 170 mph on "a french airfield" in 1972 come from ??
    Has this been mentioned here anywhere ?
     
  12. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    As mentioned previously, "frontal area" is the key here.

    A faired Commando is decidely slim if looked at from front on.
    The Honda Blackbird, mentioned here already, is not so slim - nor is its front wheel.
    The Guzzi V8 with dustbin fairing is only a few feet high, and slim....

    Someone here packed a Ford V8, as a replacement for a motorcycle engine, into an old aircraft fuel tank, with seat and wheels. Sits about 18 inches high, so is about 50% faster than anything else in its class. Its own trend on pommiejohns chart.... ?

    P.S. "Its own trend" is probably the answer to pommiejohns question.
    When we have enough streamliners, and full fairings, and dustbin fairings (and bikini fairings ?) and naked bikes plotted, each of them will have their own trend lines - all blending into and over each other....
     
  13. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    Fred Eiker will be back at the saltflats this fall to make another attempt at the 1000cc unstreamlined fuel record. He will be trying a new cam and bumping up to 920cc JS lightweight pistons to reduce the violent vibration he has previously experienced with other heavier large diplacement pistons.

    155mph is the speed to beat and I invite anyone to try to best that with an unstreamlined Nort on the salt flats - but be prepared to be disappointed because of the high elevation (low engine performance) and rolling resistance of the salt.

    Fred & I were competitors back in the day and scored 1st & 2nd at the Laguna seca national 750 cc BOTT in 84. Now we're working together to beat a land speed record. If he gets it this will be the only LSR owned by a Nort to my knowledge.

    Stay tuned and give your support.

    Jim
     
  14. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Interesting post Jim ( and for the pic Ken), we wish you and Fred well, thats a mighty performance already.

    Just out of curiousity, do you have any figures for engine performance for this ?
    Or have tried it for speed anywhere at sea level on a tar road ?

    It also raises the question of what is the fastest speed ever clocked on a naked motorcycle ? There must come a point where just hanging on dictates a terminal speed ?
     
  15. pommie john

    pommie john

    Joined:
    Nov 18, 2005

    Second post of the thread.
     
  16. pommie john

    pommie john

    Joined:
    Nov 18, 2005

    Hey ! I've done all the work here, someone else can make a new chart. :D
     
  17. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Norman WHITE now owns that bike the link refers to.
    Ex-JPN person, rider and bike builder.
    Now fast bike builder...

    Anyone got any details of a "french airfield" ??
    Or the year involved ?

    Did Norman Hyde ever have anything to do with JPN. ?
    (Google currently doesn't google, which is ominous ?).
     
  18. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    For anyone who doubts that aerodynamics is important.
    With wings this Norton could fly ?

    Bit before the Commando though.
    Geoff Tanner, on a dustbin Norton in the 1957 TT.
    (Thanks to Mortons Media for the pic)

    [​IMG]
     
  19. Seeley920

    Seeley920

    Joined:
    Jan 6, 2009
    Norman would own it...he built it! It's not an original, but the one he currently races, one of a batch, and Pommie John has ridden one of them!. I doubt that it would actually pull 170mph though, but 150mph, I wouldn't doubt. I've raced against it and it is pretty quick!

    Norman Hyde had nothing to do with JPN, he was a Triumph development engineer working on the triples with Doug Hele's team
     
  20. mike996

    mike996

    Joined:
    Oct 29, 2006
    But didn't this thread start re REAL Norton Commandos, not one-off or racing machines? An over-the-counter Norton Commando that you or I would have purchased from a Norton dealer might have managed 120-125 at the most. Talking about modding a commando to do the kind of speeds being discussed seems to me to end up with bike that has rather little to do with a stock Commando. Why not buy a current Ducati twin if you want to go 150+ and actually have a bike designed to do that.
     

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