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Commando Top Speed? (2010)

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

  1. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
  2. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    As the yough whipper snapper James is ? should be ! well aware , as he knows everything , this old dunger was timed at 160 mph , in the south Island .

    [​IMG]

    running Methanol . 72 750 5 speed . The bloke walking is walking as I had wheeled his RD 350 out of the gate , as I had gone for a walk .
    So they went for a walk . When they got there .
    But they wernt in when I got there , so I removed the offensive material .
    After all WHO would ride a RD350 , if the had a S S Imola Ducati . :shock: :?
    Both spotty faced youths in the picture raced Ring ding 350s in RD Prod .

    Not wishing to scratch the paint on fine pieces of enginneering , dispoables were a equitable move. if boreing .
    if you discount getting excited . And non profitable . After all , theres another 50 spotty faced youths doing Exctly the same thing , in the Field . :?
     
  3. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    This old Dunger , 16.9 @ 81 in the Q mile , out accerated the XS on the way back over the mountain from the sprint meet . ( met Orig. perfomance Specs )
    :shock: ( well , in acceleration at least . :lol: ) As bought 1951 BSA BA10 , 10:1 Comp , Baffles ' fell out ' , one or two others expired , valves sunk somewhat .

    [​IMG]
     
  4. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Apart from the glitch in Jims name, 1up3down is perfectly correct in his memory of Commando horsepower discussions - it has been repeatedly mentioned all along that Commandos have about that many rear wheel horsepower....

    BTW, Commando with a claimed brochure 60 bhp and Black Shadow with a claimed 55 bhp (at the engines) both have similar claimed top speeds, so rear wheel horsepower must be quite similar...?
     
  5. 1up3down

    1up3down

    Joined:
    Jan 12, 2011
    1up3down admits to encroaching senility
     
  6. hobot

    hobot

    Joined:
    Oct 19, 2005
    A decade ago DynoDave reported a hand full of hopped up street Cdo dyno results to find his own small port 750 won with ~49 rwhp, the others 47-48, so w/o hop up 750's realistically can put 45 hp on the rear patch.
     
  7. J.A.W.

    J.A.W.

    Joined:
    Jun 6, 2012
    So maybe, that Cycle Superbike Commando that made 49rwhp WAS a proper Combat, & it was the "readings" by the Cycle guys that got it wrong in seeing a SS cam not realizing that it literally meant 2S's = Combat, not SS as in old `60s 650 cam? Anyone ever spoken to the tuners, or heard from Mike Jackson about this?
    Matt, did you EVER see the Glynn Simons PR Commando run? What did he road ride, Suzuki wasn`t it? & As for race bikes, he RACED TR/RD 350s didn`t he...did you ever see a document ,or any kind certificate to verify thay mythical 160mph run? Well, huh, no didn`t think so, more ancient fantasy then ?
    At the risk of being mistaken for a Ducati forum, here is an excerpt from a `74 M.C.I. of the 'fabled' Ducati 750 SS by Dave Minton , P.22;
    "Top speed, like acceleration, took longer than might be imagined to materialise. In fact, I was never able to discover exactly what the bikes ultimate really was due to the continual creep up the scale even over 122mph after a 3 mile run in."
     
  8. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    Its Because THE WORLDS GETTING SMALLER , so they dont have so far to go , year after year . :p :p
     
  9. J.A.W.

    J.A.W.

    Joined:
    Jun 6, 2012
    & the distance between your ears, Matt, as the bat flies? Down to `bout 40 thou, on its way to ciggie paper...L.O.L.
    Ah, the 5th dimension beckons...
     
  10. Jagbruno

    Jagbruno

    Joined:
    Jan 6, 2014
    What? This post has been dormant for 3 years!!!?!

    Here I come...i recently had my first track experience on my Norton racer, and although I am obviously a pretty bad rider, the bike seemed pretty fast...

    So, the bike is a Slimline Featherbed, with a Dunstall longer box section swingarm, Commando fork, full Dunstall fairing, 18" alloy rims and road Avon tires (yes, it is my road bike as well)...Fournales air/hydraulic shock absorbers. The bike is probably significantly lighter than a Commando and is definitely lower. i weigh 72kgs and I am slim.

    Engine is 850 Commando, with PW3 camshaft, lightened crankshaft balanced for the frame (don't know the exact factor, but it works), much lightened rockers (Dunstall most likely), black Diamond valves with race springs, polished rods, flowed 32mm head, rubber mounted twin Amals MK I 32mm with splayed manifolds 260 main jets and velocity stacks, Pazon ignition, Dunstall exhausts. Stock primary transmission, 22/42 secondary. 20% Avgas.

    https://farm9.staticflickr.com/8839/179 ... 5e_o_d.jpg

    So, in Dijon, the circuit has a pretty long straight (close to a mile I think) that starts as a steep climb, keeps going slowly uphill for most of its length before going flat for the last 1/8mile. Tucked in the fairing, I spotted my magnetic Rev counter flirting with 7500-7800RRPM and my odometer wobbling around 130Mph.

    A friend of mine, riding a Vincent Black Lightning that was previously clocked there at 131Mph told me he could just about follow me but not pass me. I couldn't quite believe that I was going at that speed, so I posted on a French forum specialized in vintage british bikes and a hot discussion ensued, several members calling me a liar or a dreamer, while others (including some who had seen the bike on the track) mostly took my defense and declared that the bike was indeed very fast.

    On the last lap of the last session, I experienced some valve float at the end of the straight and immediately lost power. It seems the valves didn't touch the pistons (we opened the engine and couldn't see anything on the pistons) but both exhaust valves were slightly bent without any other problem whatsoever anywhere else in the engine.

    A calculation based on the Norton data shows that if indeed I was revving at 7500 Rpm with a 22T my speed was about 130Mph at that point.

    Do the eminent members of this forum feel it is plausible or simply a vast exageration from my Smiths magnetic instruments?
     
  11. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    It was flogged to death back then....

    Wasn't riding your bike, so don't know.
    Tell us what gearing you are running, sounds like calculations show it was possible.
    A strong engine and a fairing are good candidates....

    If the valves are bent, they must have touched something.

    Can't view your pic - it opens and then shuts down ?
     
  12. hobot

    hobot

    Joined:
    Oct 19, 2005
    Yeah Rohan is sure to imply you and the Vincent guy lie like stinking drinking fishermen. None the less you know what the wind blast and ground covered was like and have math to back it up. Other Nortons even Manx can pull over 130 so I believe ya with engine evidence to prove you are hard hearted enough. Smith clocks can be steady accurate to 1 mph plus somewhere close to 130 - tire will expand a bit so adds some drive ratio that tends to lower speedo reading vs actual speed. A cheap GPS maper gives accurate speed in levelish beelines and pretty cheap data recorders for the basic objective data to share. Let us know how hot the tranny and chain and tires feel next time using up rare exotica before you are gone.
     
  13. WZ507

    WZ507 VIP MEMBER

    Joined:
    Dec 26, 2013
    With the stated gearing and engine speed you could be seeing speeds in the 130-135 mph range. One of the wild cards in the gearing calculation that can nudge it a bit in either direction is tire size. With you seated on the bike with feet off the ground, what is the distance from the ground to the center of the rear axle (likely in the range of 12.5-13.3")? Using this radius to determine tire circumference should provide a better estimate based on gearing only. And no, I won't be including tire growth in the calculation.

    If anyone else is having trouble seeing the picture of the Jagbruno Norton racer here it is. What a beauty!
    [​IMG]
     
  14. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Thanks.

    hobot seems to be having reading comprehension difficulties again,
    I said its entirely possible with the right gearing and full fairing.
    With taller gearing, it might have enough mumbo to go even faster.
     
  15. frankdamp

    frankdamp

    Joined:
    Oct 7, 2005
    Come on you clowns - the stock Commando can manage about 105 mph. On roads with a 70 mph limit and with all those myopic old ladies in their Olds 98s, do you really want to go any faster? Maybe you track riders do, but you're not typical of our members here.

    I haven't ridden on the street since we came to America in 1968, even though I had over 20.000 miles testing the Commando in the UK. It was scary enough getting used to driving a car on the "wrong" side of the road. At least you have the visual cue of sitting on the opposite side.
     
  16. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    With a 22 tooth sprocket on the gearbox, it should do about that in 3rd.
    And pic shows a fully faired bike, and strong engine from the description.
     
  17. 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...
     
  18. 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....
     
  19. 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.
     
  20. 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?
     

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