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Commando Top Speed? (2010)

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

  1. hobot

    hobot

    Joined:
    Oct 19, 2005
    There is the Texas Mile for sea level pavement all out testing.
    Would a steel flywheel prevent entering in stock class? Carb size?
    I quiz them while in Texas this weekend.
     
  2. Seeley920

    Seeley920

    Joined:
    Jan 6, 2009

    You can read all about it here!!

    http://guskuhn.net/GKMLtd/GKM Intro.htm
     
  3. hobot

    hobot

    Joined:
    Oct 19, 2005
    Wow facinating reading for quotes like this.
    30 mph is like a gear shift ahead of the rest and makes them feel like a slalom run among parking lot cones to leave one thinking they are such corner cripples. hehe

    Gus also mentions a fairing with such power should give 145 mph Commando.
     
  4. Rich_j

    Rich_j

    Joined:
    Jun 7, 2009
    I was talking to Norman White today on another matter today but dropped in the top speed question.

    The best the factory bikes did according to the man is 152mph at Daytona from 72hp with a lot of work done on aerodynamics.
    He also mentioned 143mph with a production racer at the IOM
     
  5. hobot

    hobot

    Joined:
    Oct 19, 2005
    Very informative Rich. My quesitmate of Ms Peel base line no boost Manny 920 is ~80 hp. I'll start off running longer duration higher lift cam than Manney but with only factory Combat port and valve sizes, so don't know how this will compare to Manney's 100 hp @ 7200. Hope its good for 150 with decent fairing and no boost
    and space enough somewhere to reach top out.
     
  6. Rich_j

    Rich_j

    Joined:
    Jun 7, 2009
    Forgot to say, Normans 72hp was crank.
     
  7. hobot

    hobot

    Joined:
    Oct 19, 2005
    Ok Rich I think better in shaft hp ratings but after years of reading dyno reports on Nortons comparing rwhp to shp there is generally only 9% drive train loss. This imples 65 rwph. Would be educational to plug the rpm data into power equation to get ball park of crank torque.
     
  8. daveh

    daveh

    Joined:
    Jan 22, 2008
    Thanks for posting those figures, Rich. Both performance figures are impressive for the period when one considers the engine design.
     
  9. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    You didn't happen to ask him what his bikes can do these days ?

    There is an Indian ohv in classic racing, engine and heads/cams built using modern thinking, that has clocked just shy of 160 mph, naked no fairing. Along the lines of Bert Munros "Worlds fastest Indian" engine, with a bit of hillclimb motor thrown in. 1000cc though...
     
  10. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    yes ..... And he tried no less than 10 camshafts before he found a 100% accurate one :!:
     
  11. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    Why has this thread suddenly come back to life ?
    And whence comes this snippet of info ??

    And, given that the 4S cam was reportedly done FROM the cam that Engineer Baker developed for this factory 850 hot-rod, and the factory 850 tuning sheets came FROM this bikes development, this snippet of info is ??? ???

    Nothing better to do on Saturday night than go trolling, Bernhard ?
     
  12. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    Given That :p if you look at the Cam lift / degree graphs elsewhere on this site , the Combat SS , and 4S show near identical profiles , and the 4S , say 20 thou. more lift overall , AND there is a ' large base ' SS camshaft , with Combat lift and a 20 thou. greater base circle , One is led to believe , that if you ground THAT
    cam .020 off its base radius ( a common trick ) , Why , One would HAVE a " 4S " cam .Though you could go about designing it by other means , and end up with
    a identical result . :oops:

    During 1969, Pickrell rode Dunstall machines to gain two speed records. One, thought to have been set on this machine, was a new national record for the 750cc flying-start quarter mile at 144.69mph established at Elvington, Yorkshire. The other, set on another Dunstall team visit to Monza, was a world 750cc record for 10 Kilometres covered at 131.51mph, which stood for seven years.
     
  13. J.A.W.

    J.A.W.

    Joined:
    Jun 6, 2012
    Dunstall lost that 10km 750 record to Kawasaki,[750/3] who were trying for the 1hr record at Daytona,but stopped when the rear tyre chunked out, still they were averaging over 150mph, taking the 10km record by a fair margin.
    Would still be good to know if that 143mph -`74 I.o.M. production racing Commando was an 850?
     
  14. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    [quote="J.A.W."
    Would still be good to know if that 143mph -`74 I.o.M. production racing Commando was an 850?[/quote]

    Which " 143mph -1974 I.o.M. production racing Commando" was this ?
    Name a rider ?
     
  15. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    I just spent a whole lot of time reading tru this thread from the start. It is quite entertaining and has made me realize that my own Commando is quite special- it only goes about 105- 110 mph, not many are that slow it seems!

    As for Commando BS stories, I heard a good one several years ago while hunting for my first Vincent. I heard that there was a trucker who owned a beautiful Vincent somewhere in the BC Interior. A lot of searching and even placement of a newpaper ad that ran in a collection of 23 small independant BC newspapers netted some info. I found the name of the trucking company that the Vincent owning trucker worked for!

    I contacted the company owner and he was very clear, the Vincent owner, Ken, had retired to a community called 108 mile Ranch. The Vincent was said to be very beautiful and very fast, though the company owner was unsure if Ken still had it.

    I called Ken and explained that I was in the market for a Vincent twin and had been told that he had one. My heart skipped when he said "yeahhhhh" then hesitated.
    " It was a Norton Commando, a special one, but I sold it awhile back" I was pretty deflated on learning that the elusive Vincent was actually a common Commando, nice that they are, but I already had one and they are readily available on Ebay or wherever.
    It was clear Ken wanted to talk about this "special" Commando, so I politely listened.
    "It was an Interstate model, the factory only built a few of them, they were hopped up and geared for tremendously high speed.
    I was touring in Nova Scotia with it, had the wife on the back, but she was asleep and I was really moving. A cop finally pulled me over and said, Sir, we just clocked you doing ONE HUNDRED AND FIFTY TWO MILES PER HOUR on our radar!"

    I didnt tell him that I had one of these "Special" high speed factory Interstates, or tell him how full of BS he was, instead we both agreed that it was a good thing his wife was asleep on the back at the time, or she might have become quite angry!

    Glen
     
  16. hobot

    hobot

    Joined:
    Oct 19, 2005
    Now that was both entertaining and educational Glen. I too want a Commando to go over 150 and so smooth my nervous back seat driver just sleeps through it till a police helicopter pulls us over, cause it can cheat and fly in bee lines over the ground. Really.
     
  17. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I believe my norton could do 150mph easily if I rode it over a cliff. I found the comment about the cams interesting. I built my Seeley in about 1978, about the time I stopped racing regularly. When it came to the camshaft department, I simply walked into one of the race shops in Melbourne, where I knew they had a nice new cam grinding machine. Chucked the old cam on the counter and said 'just give me your best norton grind' - knowing that what ever that might be, I could probably get sense out of it. When it came to timing the motor, I heated the sprocket to soften it, and had two more keyways broached in. The initial timing looked as though the cam was combat profile, and because I am using a two into one exhaust, I advanced it 15 degrees from standard combat settings. It means that the exhaust closes early, but with the pipe the result is excellent. For the last ten months I've been stuffing around fitting a six speed box to the bike. When I had the fight with the sprockets and chain adjustment, I believe I must have ended up one tooth too high on both the engine, and gearbox drive sprockets. Day before yesterday, I took it to Winton Raceway to fire it up and get sense out of it. After a lot of stuffing around, we finally got it going, and I decided t o ride it around the pits. I had fitted the gearchange lever too low, but I am certain I was in first gear. The gearing was absurdly high, but the motor still pulled it. I gave it a short burst down the next pit lane which was empty, then back up the next, slipping the clutch to get it going. It took off like its backside was on fire and for a split second I thought I was going to take out the fence at the end of the lane . I grabbed a big handful of brake. When I raced the bike for the first time years ago, it was over revving but going nowhere, so I upped the gearing to knock its backside in, - it simply went faster. The effort the other day amazed me, I would not have thought it had so much torque. One thing I believe in, is that the table in Phil Irving's 'Tuning for speed' is a good guide towards optimal timing, especially as it lists the 1959 7R AJS which was probably the best 350 of its time. I've used a two into one pipe on my short stroke Triumph 500 years ago, but had the advantage of separate cam shafts for inlet and exhaust. I learnt a couple of things - the tail pipe must be as big as the total area of the two header pipes, and opening the exhaust before 85 degrees before BDC makes the exhaust louder, and the bike slower.
    I know all this stuff will sound crude to you guys, but it actually worked. I've only raced the bike a few times about 8 years ago, but first time out I won a couple of races at the old farts meeting at Mount Gambier in South Australia. It has been difficult to ge t off the line with the old four speed CR box - hence the new six speeder is now fitted. The boxes with the high first gear were great when we had push starts years ago, the se days everyone uses five speed boxes with a very low first gear for the clutch starts.
     
  18. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I am very suspicious of standard commandos. I believe Norton tried to do two things and ended up with a compromise, doing neither very well. The 58% balance factor is stupidity if the motor is going to be revved hard, I have a set of cases which have split through the drive side bearing. The isolastics might smooth out vibration for low speed riding, but for high speeds they are suspect. The cam timings used might have also been designed to give smooth low speed performance .
     
  19. hobot

    hobot

    Joined:
    Oct 19, 2005
    Wow wee acotrel, your experiences are priceless data points for Ms Peel. I've saved your wisdoms to try someday. I don't think Peel accidental power combo was as wild as yours but sure amazed me and others, especially after upping the drive ratio to use the Torque up. If ya ever get too close to stop in line, you can lock both brakes up and turn bike completely sides ways to slide both edges and frame rail or peg to slow up quicker. Better slower low side into something than helmet and forks first. Someone should get a Commando going that's 150 capable w/o shaking apart.
     
  20. Rohan

    Rohan

    Joined:
    Aug 26, 2010
    You don't hear much about this bike ?
    In fact, other than being in the brochure, never heard a word on it. Except it inspired the road bike version (?)(which looks quite different).
    It was of course a 750cc, since thats the class it was in...
    [​IMG]
     

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