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Commando Top Speed? (2010)

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

  1. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    You keep repeating this myth/pseudo science.

    Road tests of the era give numbers to speedo accuracy.
    About 4 or 5 mph out at 60 mph was common.

    If you haven't greased your speedo/tacho cable lately, needle flicker could easily cover bigger range than that...
     
  2. hobot

    hobot

    Joined:
    Oct 19, 2005
    Ugh - the Smiths can be 1 mph steady through its reading range following its drive system but it can not compensate for the various factors listed above nor can most other installed non GPS speedos and GPS does not compensate for significant slopes so still as good as it gets w/o tripping light beams. I have read up on Smiths so quess next step to quell your public wrath is ping them directly. Anywho it took a 130 mph Commando to keep me enthused beyond nay sayers. Annoying lift out of seat bothers my featherweight body to knee grip tank going faster, more so when cresting....
     
  3. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Waste of time. These are 40+ year old instruments, who there now is going to be able to say reliably anything meaningful.
    How can they possibly be all accurate to 1 mph, they were cheap back then.

    Magazine tests when they were new measured them at MIRA (Motor Industry Research Association). Speedbowl, instrumented.
    Indicated speed. Actual speed. Generally 4 or 5 mph out at 60 mph.

    Now, these newfangled electronic ones may be a different kettle'o'fish.
    As anything GPS based too.
     
  4. Old Scratcher

    Old Scratcher

    Joined:
    Mar 1, 2015
    Top speeds are all well & good. I've modded a few motors in my time, mainly Triumph twins, & it's surprising how much hp can be unleashed if one's prepared to spend enough. But spend you really have to do, especially when chasing the upper reaches of what's attainable, with every extra Pony costing twice as much as the one preceding it. & there's no doubt that it comes at a cost to the longevity of the motor. Metal that was only engineered to take 50hp will suffer long term structural damage if it has to cope with 80hp+, & it's life span will be shortened accordingly. Anyway most of our bikes have reached an age where it's unkind to subject them to anywhere near their redline, no matter how well fettled they might be. Though I'm sure plenty still do, & I'm not criticising. Your bike, your choice! But I'd like to know what speeds most people cruise their bikes at? What is their RPM sweet spot? Where their Commando can just run sweetly all day. & at what speed/revs do you consider it abusive to subject a 40+ year old machine to? I realise that there's going to be wide diversion of opinions, & I'm not looking for the "right answer", as I don't think there is one. So all opinions will be respectfully examined by me, & my only hope is to get as clear an idea of the consensus of opinions as possible. So at which RPM/speed do you think the line between use & abuse lies?
     
  5. snakehips

    snakehips

    Joined:
    May 8, 2005
    Continuous 4500 max through the gears 6000-6500 unless of course were talking about when I was thrashing her round Mallory Park to within an inch of her life must of taken years off her life. :eek:
     
  6. hobot

    hobot

    Joined:
    Oct 19, 2005
    Every cycle and scooter I have tried always felt best cruise harmonics between 3500-4500 rpm, regardless of the speed that produced. All of them but the Cdo, be it a big or small scooter or Goldwings, rubber mounted HD or Suzuki inline 6s transmit valve buzz that becomes annoying presence to me after 10-20 min, even if so mild it does not numb or tingle hands or feet, their engines just do not disappear or cut the vibe peaks out like a clunker Commando. By far the worse injurious vibrator was my P!! at speed. It is interesting and revealing to feel a Commando transition from flying carpet smoothie to biplane fabric-cable flapping bi-plane when it leaves the ground for some rough riding air borne time. To play a potent Commando with squids and mature sports riders in the best/worse sections of Ozarks, which is similar to Barbers track but 1/4th the width, Peel could not let rpm drop below 6000 - sometimes for over a 100 miles in about an hour of getting low 30 mpg mileage, so must stay a bit aware of gas tank range & slosh inertia changing.
     
  7. hobot

    hobot

    Joined:
    Oct 19, 2005
    Just spoke with Tom Kullen in Utah who is Northern Western hemisphere Smith vendor and assured me Smiths can work as accurate as any spin driven speedo through their whole range. His isolastic Commando 750 racer will reach over 130 and amazes famous modern bike racers, such as some Shane fella on its power and turning load handling to point of drying their teeth out on wide shit eating grins. Tom is severe XX Black Diamond snow skier trainer during snow season and a wild man inspiration to me. Please ping him to be pumped up on Commando and help pump him up on what he is having to endure over come with rare cancer and medical procedures. http://kullendesign.com/smithgaugewebsite/contact/
     
  8. 1up3down

    1up3down

    Joined:
    Jan 12, 2011

    very true

    the book that I have of all the Commando road tests consistently shows Smiths' speedos in significant error
     
  9. hobot

    hobot

    Joined:
    Oct 19, 2005
    Again when Smiths working as designed they are as accurate or more so as any spin driven speedo. Not hobot opinion so sorry if yours and test cycles were not up to snuff. On both Peel and Trixie I have ridden next to cars an PUs shouting back and forth on speedo reports to 70 mph then hand signals d/t air blast. Also pleaded with some vacationing Yamaha racers here to see if their speedo matched Peel Smith showing 130 but they would not run up as fast as Peel even if their cycles could, which was both disappointing as did not get their feedback after they assured me they would run up that fast in opens and elating on Peels pecking order. Hehe upset online reactions to hobot do not come close to the face/face expressions aimed at me/Peel on various encounters so sorry if you all do not know what ya missing out on. I only wish others could share my joys before we are gone as surprised shit out of me no end too but becomes addictive-obsession so beware. The events were like knock down drag out fights at time with similar after effects, some lasting new friends to permanent enemies.
     
  10. Old Scratcher

    Old Scratcher

    Joined:
    Mar 1, 2015
    The most "optimistic" speedo I've had was on a Kawasaki KLR 600. Mind you, it was a mixed blessing. I got booked one day, while the needle was well north of 160kph, which would have been on the spot loss of licence. But the radar gun only showed 143kph, which was still an expensive ticket & loss of licence points, but a at least I wasn't walking off to look for someone to tow my bike! :lol:
     
  11. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    Remember that the Smith's speedo is adjustable. You can get them as accurate as you need to.
     
  12. Jagbruno

    Jagbruno

    Joined:
    Jan 6, 2014
    Well the problem is that at high speed/revs, the needles on both of them tend to wobble quite a bit...during my circuit experience 2 weeks ago, at the end of the Dijon straight, slightly uphill, my speedo was indicating anything between 120 and 135Mph while simultaneously, my tacho was showing 7000/8000 RPM...obviously, my bike is a Featherbed with a moderately tuned engine in it, no isolastics, full Dunstall fairing, Dunstal box section extended swingarm, lightened crank and rockers, PW3 camshaft.
     
  13. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Just riding on a rough road will see some needle jittering, never mind the engine vibes.
    The instruments don't have their own isolastic mountings !!

    Incidentally, the tacho on the manx etc does, it has a big rubber doughnut the tacho sits in.
    So Smiths were well aware of the vibes causing problems.
     
  14. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    On the bench.
    The aforesaid vibes, even from less than smooth roads will still give some needle jitter.
    Especially at warp speeds, Mr Spock.

    And its not exactly a simple DIY adjustment either, is it. ?
    You have to destroy the chrome bezel ring just to be able to get into them.
    And be able to satisfactorily neatly crimp a new one back on.

    The idea too of speedos slightly over reading is that assists in keeping road users UNDER the legal speed limit,
    rather than over it....
     
  15. pete.v

    pete.v

    Joined:
    Oct 31, 2009
    I bet with new dunlops properly inflated, the speedo's are pretty close. Warn Avons, not so.
     
  16. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Interesting point.
    Do modern tires have a larger diam /rolling circumference than tires of old.
    Some of these low profile types would be less ??
     
  17. hobot

    hobot

    Joined:
    Oct 19, 2005
    For 1000s of mile intervals between rear drives wallowing out rivets then ring gear or 90* shaft cogs crumbling, or wrongly inserted cable and cable snatch apart wrapping wheel to short stop, needles were steady as my cars so was tachs on 2 Cdos so that has spoiled me how good they can be, even if like chains or tires or AAU, all good things...

    I want a speedo on racer as can creep up to loss of control speed then mark in mind so can think of other stuff enjoying each corner.

    Any queses how fast next Peel might go? Ken assures me over 150. No way to out hp to top speeds of good sports bikes so hope torque can out accelerate more power planting time to make up for the loss of ground in long opens. BFD if some 200 hp cycle can run a freeway faster, its dicing decreasing clover leafs that revs me up.
     
  18. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    Incorrect. The adjustment is through a hole on the speedo's base. You can get at it with a small screwdriver.
     
  19. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Where ?

    This is the Smiths taken off a 1973 850, a few years later.

    [​IMG]

    Nothing appears to be accessible through the hole for the little light bulb,
    except the back of one of whatever it is that holds on the speedo face.....
     
  20. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Once the illuminating light fitting is fitted, these are more or less sealed.
    A 'little hole' would let dirt and dust in...
     

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