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Commando Top Speed? (2010)

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

  1. Carbonfibre

    Carbonfibre

    Joined:
    Nov 16, 2010
    Sorry I thought your supercharged Norton was able to beat any Jap 4 cyl sports bike, not just things like stock SV650 twins? If you turn up the boost would 200mph be possible I wonder? Running those sorts of speeds you would obviously need to have that trick modified crank of yours fitted, to reduce vibration at engine speeds higher than 12,000, but should be very impressive!
     
  2. pommie john

    pommie john

    Joined:
    Nov 18, 2005
    Hey, this thread's still going!

    I think everyone's made their point but I'll finish by paraphasing CR Axtell from an interview I read somewhere about his tuning of Norton Commandos.

    First we broke pistons, so we used better ones. Then we broke cranks so we strengthened them. Then we broke the crankcases. There's only so much you can do with an engine.

    I'll admit I can't remember the exact quote, but that was the essence of it.
     
  3. john robert bould

    john robert bould

    Joined:
    Sep 26, 2009
    I remember my mate showing a work van what for...he had be following it for some miles on his 69 fast back...the guys peaking from the back window where gestering,,,so my mate changed down into second at 60mph...the rods decided to have a look outside :!:
     
  4. Carbonfibre

    Carbonfibre

    Joined:
    Nov 16, 2010
    On blown Nortons able to top 160mph all engine problems are easily avoided by fitting very special lightweight race cranks, that allows safe operation up to and above 12,000rpm. In conjunction with the outstanding MotoGp type handling of the bike in question, this means lesser bikes such as race tuned R1's are easily blown into the weeds!
     
  5. bwolfie

    bwolfie VIP MEMBER

    Joined:
    Sep 21, 2010

    Carbonfibre, it is time that you start to grow up and use this forum for what it is intended for. Sharing information and advice. Please take your sarcasm and negativity else where. I'm sure I am not the only person that feels this way.
     
  6. daveh

    daveh

    Joined:
    Jan 22, 2008
    Yes, this forum should be about sharing information and advice, and should be respectful.

    As Ludwig has remarked, riding in the mountains is 90% rider and 10% bike. If the rider is experienced and knows the road, and the road is twisty, and throw in a bit of gravel or cow shit on the corners or some damp leaves under the trees, then modern bikes cannot be exploited to anything like their full extent. There are roads like this in Ireland on our regular Sunday runs. On these roads, an inexperienced rider will struggle on a modern sports bike with a Moto GP riding position, super-sensitive brakes and huge power.
     
  7. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    Don't forget GOATS!
     
  8. bwolfie

    bwolfie VIP MEMBER

    Joined:
    Sep 21, 2010
    Dam goats!!
     
  9. Carbonfibre

    Carbonfibre

    Joined:
    Nov 16, 2010
    Carbonfibre, it is time that you start to grow up and use this forum for what it is intended for. Sharing information and advice. Please take your sarcasm and negativity else where. I'm sure I am not the only person that feels this way.[/quote]


    Certainly............but when posters are suggesting their bikes are able to blow Jap sports machines into the weeds, and are capable of 160mph, I am not entirely sure whether or not such claims are likely to be helpful to anyone?
     
  10. bwolfie

    bwolfie VIP MEMBER

    Joined:
    Sep 21, 2010
    Steve has spent many years and collaborated with many people to get his bike to the point it is at. He knows what is going on with his bike. That cannot be said about the general population of sport bike riders. Old technology is not necessarly slow or bad. Proper setup and component selection can yeild a superior machine. I recently purchased a gsxr 750 as a donor bike. What a pig. It is built way too heavy. It puts out around 100 HP at best. Crippled by it's own weight. And it needs to be in the upper RPM range to really get going. A Commando engine setup with crank rods pistons induction and exhaust mods plus a supercharger and good carburator will produce a wider mor usable power band.
     
  11. mrlee

    mrlee

    Joined:
    Oct 7, 2010

    Certainly............but when posters are suggesting their bikes are able to blow Jap sports machines into the weeds, and are capable of 160mph, I am not entirely sure whether or not such claims are likely to be helpful to anyone?[/quote]


    Its true that some of the stories on here reek of the fish that got away tale, but at the end of the day, all of us are here bc we love Nortons .
    Lets keep it civil , eh?
    Davidlee
     
  12. Carbonfibre

    Carbonfibre

    Joined:
    Nov 16, 2010
    Old technology is just fine, but it is a little silly when you see people suggesting that a bike fitted with an engine whose basic design was arrived out 40 yrs ago, with a frame from the late 60's, is able to easily eclipse a modern Jap sportsbike with double the power, and far superior handling and brakes.
     
  13. Mark

    Mark

    Joined:
    Aug 8, 2006
    We get your point already, Jeesh! Give it a rest!
     
  14. Jeandr

    Jeandr

    Joined:
    Jan 22, 2008
    My formula is:

    Mph = rpm x .00297 x tire diameter in inches / overall gear ratio

    For example, a K81 4.25/85 H18 has a 25.5 inch diameter, a normal Commando has a 4.730769 overall gear ratio in top gear with a 19 tooth countershaft sprocket.

    Mph = 7000 x .00297 x 25.5 / 4.730769 = 112 which is about what I saw indicated on the speedo, the real speed may have been a bit lower.

    Now, to get a Norton to 130, 150 or 160, the engine must turn a whole lot faster or the gearing must be changed. What is the size of the countershat sprocket needed to get there assuming we keep the same 7000 rpm maximum engine speed?

    for 130 the countershaft sprocket will need to be a 23 tooth, for 150, a 26 tooth and for 160, a giant 28. While a 23 tooth sprocket is available, it would limit acceleration in the lower gears to get the high speed as for the others, I don't think they are available and the accelaration would suffer even more if thew were. While it could be said the engine could be reved faster, I don't think it would survive very long at higher than 7000 rpm, especially while trying to produce a lot more horsepower to acheive those speeds.

    Jean
     
  15. cash

    cash

    Joined:
    Nov 10, 2006
    Jean,
    Did you take into account the tyre caterpillar effect. :wink:

    Cash
     
  16. grandpaul

    grandpaul VIP MEMBER

    Joined:
    Jan 15, 2008
    Couldn't a different primary drive ratio give you higher speed without so many teeth on the mainshaft sprocket?

    Couldn't a smaller rear drive sprocket also give you a higher ratio without such a big mainshaft sprocket?

    Also, reasonable cam, crank, rod & piston swap would certainly yield higher safe operating RPM...

    Re-calc!
     
  17. mrlee

    mrlee

    Joined:
    Oct 7, 2010
    So let me get this straight, you dont think an old Norton can outrun a modern bike? :D :D

    Roger that .
    I like your knowledge of bikes but I'm a little perplexed why on a Norton forum , where exagerations may or may not occur, you keep slamming our beloved marque?
    Best regards
    david lee
     
  18. mike996

    mike996

    Joined:
    Oct 29, 2006
    OK, I gotta say...I owned my Norton Commando and my Ducati 996 together while living in NY, before moving to Mexico. I regularly tracked the the Duck at Lime Rock in addition to riding all over NY. There is NOTHING that the Norton could do in any way that could come close to matching that Ducati as far as performance is concerned. The Duck could easily outrun, outstop, out handle, and out-anything else I could do on my Commando. THe difference wasn't minor - we're talking several orders of magnitude.

    In late '06 Ihad to decide which bike I wanted to take to Mexico when we moved there due to work.

    I sold the Duck...

    The Commando is more fun for some retarded reason that I can't figure out! :)
     
  19. hobot

    hobot

    Joined:
    Oct 19, 2005
    Carbonfiber may be annoying especially to me but he's is not being irrational, he's just operating as I too once was from a lack of experiencing what's possible on a clap trap Commando with some bugs worked around.

    How would you sound if your Commando was the one that had that much black and white advantage - on anything but pure drag racing. Its was the 1098 that made me lose a few years getting upgraded to Maney 920 to drop boost on instead of 750. I'm besides myself to get more power for faster turns and will enjoy what ever top speed that also allows. So leave Carbonfire to his own judgements made public vs mine and if we live long enough see who eats what.

    My firm opinion now is it its got a steering damper or fat tires and needs traction control, its ain't no concern to Ms Peel until upright again, for some distance so the poor things can gather their wits and not just claw at the sky.
    I read about the bind faith of new racer pegging the throttle of 200 hp to take turns and wait and wait till they get about upright to add in much power. hehehe even then corner cripples step out jitter and skip unintended, while me on long tooth Peel has to work my ass off to get her to do that except on THE Gravel. If ya think there is any difference tarmac to Grit when traction is missing, then ya just ain't lived enough of yet.
     
  20. pommie john

    pommie john

    Joined:
    Nov 18, 2005

    I'm going to come to the defence of carbonfibre. I think he has been sensible and made relevant points. He's probably exasperated at the way commonsense has been ignored by those who make claims that don't obey the laws of physics.
     

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