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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
    The usual cause for splitting through the bearing housing is piston seizure !!
    When the piston stops, the crank has no-where to go, and escaping is about its only option.
    Common sight at classic racing - across a wide range of brands.
     
  2. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Tall stories about speeding tickets are commonplace.
    Like fishing stories, you should always ask to see the fish involved.

    BTW, any good lawyer could have got him off = the radar was obviously faulty, since a road Commando cannot do that speed.

    BTW2, Commandos geared to do 150+ mph are not that simple - the selection of sprockets doesn't quite really go that high. Have a look at how the factory racers did it.....
     
  3. Snorton74

    Snorton74

    Joined:
    Jul 28, 2012
     
  4. hobot

    hobot

    Joined:
    Oct 19, 2005
    Commandos are about the most dangerous corner cripples I've ever survived but they can take the bee lines as good as any till the tires blow out. Ken Canaga and John Magyar both reviewed us on 160+ mph ratio comb's but always good to be refreshed again. A 150 mph daily commuter would need the lowest first ratio as no proper size CVT available, either too small or too big for a Cdo strong enough to pull to 150 quick enough to do so now and then and not get caught. Do you know how fast it takes not to hear WOT siting on a Cdo?
     
  5. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    And what is the fine for doing +150mph. ??
    In some places, its jail, + throw away your license,+ $$$
    Well worth proving that some country cop sat on his radar and trashed/un-calibrated it.

    Some computer nerd challenged the computer code that calculated the speed - and won.
    Seems whoever programmed those things wasn't very good at calculations - and under scrutiny wasn't correctly done. They keep that one pretty hushed up....
     
  6. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    Yes , ring dingers think that if you dont engage them at traffic lights , theyve blown you off .
    A H2 came up beside me on the bottom leg to a T , Left & building ahead , right and Uni Students & Traffic .
    Put it in Neutral & crossed arms , was upwind too . The cacacophony shortly departed .
    After pauseing to see it haddent had a accident , and waiting for the noise & smoke to clear , we proceeded to enjoy the sunshine & peacefull day .
     
  7. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    " Dunstall took the lead in England's performance race and ran with it; setting records at Monza with 126 miles covered in one hour, and a stunning 17 first-place wins in 1968. This included a Ray Pickrell victory in the Production Class at the TT setting a new lap record averaging 99.39 mph."

    Though the suckers have the Dual loop Chassis , essentially , it is the Commando Powerplant / Transmission . Etc .

    Typical Race Dustall .

    [​IMG]

    Only a half mile to the finish line .

    [​IMG]

    For NORTON entusiasts . ( Monza , in Er , this forign language . )

    http://chopsueygarage.blogspot.com.au/2 ... chive.html

    [​IMG]

    But the RD 350 LC dohc turbo nitro supercharged , the year before , did it at %00 , :oops:

    The Yan GP racer , being a rule twister with 200 ' Race ' engines homlogated , perverted the regulations intent that the ' formular ' racers were
    proveing PRODUCTION based machines , the 200 allowing for smaller manufacturers , such as Ducati , to comply .

    Unfortunately , there was a buck to be made , and it was all downhill from there .

    Some people believe the car that set FTD on the Targa Florio stage of the England / australia rally , was a Lemon. A Primeminster even ,
    But they say here you cant trust polititions .

    [​IMG]


    http://www.leylandp76.com/publications/ ... ainfo.html

    I think weve coverd industrial espionage elsewhere ?
     
  8. J.A.W.

    J.A.W.

    Joined:
    Jun 6, 2012
    Rohan, in`74 for the I.o.M. P.R. TT, the capacity limit was raised from 750cc, so Laverda & BMW could run their big mills.
    The factory Nortons were entered [but D.N.F`d] including P.W., & the race was won [again] by a 750 Triumph.
    If anyone knows, were the Commandos 850s, or possibly even short stroke 750s?
     
  9. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I've been having discussions with an old friend who raced mainly in the sixties. His theory is that trhe motor should reach maximum revs 80 percent of the way down the longest straight. This raises a question in my mind about torque characteristics. I believe that most dyno runs usually concentrate on a max horsepower reading and probably don't map the torque characteristics. There is an old saying 'torque wins races'. My old Triumph had 63mm stroke, long rods , and the pulling power was all top end. I rode it at Phillip Island years ago and at the end of the section from Southern loop to Honda corner passed most of the guys in front. I slipped under two in the corner and did similar going towards Siberia. I just touched the brake, and it locked instantly, and threw me down the road at over 100mph - all on non-skid surface. My Norton is completely different, I try to keep it on max torque, but I don't really know at what revs that occurs. I believe that due t o the high first gear of the 4speed CR box I've been using, I've probably kept the overall gearing too low. As the motor spins up through the gears it reaches its limit almost instantaneously, hard not to over rev. The six speed box should be interesting.
     
  10. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Dyno runs map the torque curve - and calculate the horsepower produced.
    Torque is a set of numbers, horsepower is only ever a calculation.

    Folks comment on the max power, but its the underlying torque curve that propels you down the road, as you say. A thread here a while back compared torque/power curves for a number of superbikes tested in the 1970s - Nortons have a reasonably strong torque curve, with a few dips in the lower rpms and run out of revs before a lot of the opposition (ie 4s).

    Gearing for tracks is a whole subject in itsself. You see sprocket sets for G50 matchies in that big stack of different sizes, factory supplied, and know someone thinks about these things...
     
  11. daveh

    daveh

    Joined:
    Jan 22, 2008
    I'd like to hear how you get on with the 6 speeder and the difference it makes. I have often wondered what it would be like using a 5 speed box instead of the 6 speed for more nadgery circuits with short straights.

    When you say you try to keep it on 'max torque', do you really mean 'in the power band'? Does it run out of breath on the longer straights?

    BTW, I think you will find that modern dyno services map torque and hp curves, at least the ones I had done gave both.
     
  12. JimC

    JimC

    Joined:
    Oct 12, 2007
    Not everyone realizes that HP is only a calculation, the total being dependent upon torque and rpm. A mild torque, peaky, high horsepower four cylinder is not nearly as much fun to ride as a big torque single or twin. One of the more pleasurable modern bikes I've ridden is a Moto Guzzi Norge. 1200cc twin with torque galore.
     
  13. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    high torque is but a good serving of horsepower at low RPM. When doing a dyno run on older dynos, torque is calculated from the horsepower result obtained. Newer dynos do the calculation for you.

    Torque = (horsepower x 5252) divided by RPM.

    But I know what you mean. A pinnacle of horsepower is of little use other than providing bragging rights.

    What is nice for the road is a load of horsepower down low, the number at the top is not important, it might only be reached for a split second or not at all, depending on riding style.
    With a lot of low down horsepower (high torque), one does not need to beat the motor to death in order to go fast!

    Glen
     
  14. JimC

    JimC

    Joined:
    Oct 12, 2007
    Actually, a brake/engine dyno measures torque and rpm from which horsepower is calculated. Torque x RPM / 5252 = HP. Same thing you were saying, only a different form.

    I haven't been in a dyno room for ages, so I imagine the newer dynos are a lot more sophisticated, but the principle remains the same.
     
  15. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    We use an old Dynomometer owned by my friend Murray Neibel, owner of Modern Motorcycles /Suzuki. His dyno produces a BHP readout and graph only. We get all of our Torque figures from that by calculating. The newer ones give both curves.

    Glen
     
  16. hobot

    hobot

    Joined:
    Oct 19, 2005
    I had a V8 dyno'd by old school water brake engine dyno in a semi trailer and it read the torque figures by the pressure plus rpm on big old needle guage and dial. Then math done to plot out hp curve. KInd of pensive to hear engine bought to peak torque or rpm then dragged back down closing the valves.
     
  17. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I found the commando engine very deceptive. The bike was quite quick and accelerating well, but it was coming up through the rev range too easily, and was difficult to stop over-revving. I took a tooth off the rear sprocket which was already quite small, and the bike just went quicker, and was just as difficult to stop over-revving. The change made first gear really uncomfortable during the clutch starts. If you lose 150 feet off the start in our historic races, you then have probably four 1000cc CB750s on alcohol to get past, and I'm too old for that stuff. I was surprised last saturday when I had set the overall gearing much too high, and rode the thing round the pits slipping the clutch. When I gave it a burst, it still took off like its backside was on fire, and even gave me a bit of a moment.
    I raced for about twelve years back in the 60s and 70s with my short stroke 500cc Triumph. My mate had a 650 which I could never convincingly beat. One day we were out at Calder raceway practising, and he let me ride his bike. I came around Gloweave Corner beside a good H2 Kawasaki which was fitted with chambers. The 650 Triumph out accelerated it, and as I braked at the end of the straight, I could hear it sliding down the road behind me - on its side. My mate's bike was always set up for torque, and was never revved over 6,300 RPM. Every other Triumph which has been used in our historic races, has blown up - my mate still takes his bike to the salt at Lake Gairdner in South Australia.

    My mate's bike is the one with the rider in blue leathers on it:
    http://www.youtube.com/watch?v=UbnGGl3m4KY
     
  18. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    That is actually an odd setup then - since a dyno can only measure the torque.
    And for an 'old' dyno, usually then calculate out the horspower figures, applying various correction factors along the way, etc....
     
  19. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Race gearing usually has to be aimed at not undergearing the bike - or you'd have to roll back the throttle on the straights(s).

    If getting the gearing right for the main straight makes starts difficult, maybe you need a lower ratio set of 1st gears ?? Are they std kickstart gears for 1st in there now, or a close ratio 1st set ?
     
  20. worntorn

    worntorn

    Joined:
    Dec 22, 2006

    http://www.pwrtst.com/news-and-articles ... r-work.htm

    Water brake measures heat (power) not torque. Torque can be calculated tho.

    Glen
     

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