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Dyno run (2017)

Discussion in 'Norton Commando Motorcycles (Classic)' started by Fullauto, Oct 23, 2017.

  1. MexicoMike

    MexicoMike

    Joined:
    Jan 31, 2010
    Really? I have never ridden a Manx but I was under the impression that they could hit 140mph which I didn't think any relatively stock Commando could manage.

    Jim, you mentioned "restricted peashooters" Does that mean that all peashooters are restrictive or just certain ones. Are the generally available ones - seems like Emgo is a common brand as is the AN "Norton" logo peashooters - considered restrictive?
     
    Last edited: Nov 10, 2018
  2. Onder

    Onder

    Joined:
    May 11, 2010
    The AN ones I have are quite loud making me think they arent really restrictive. At some point AN said they are working on new
    peashooters. Maybe they still are.
     
  3. gortnipper

    gortnipper VIP MEMBER

    Joined:
    Nov 11, 2013
  4. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    The restricted peashooters were just the late factory peashooters. The hole in the end was about the size of your thumb. They were used with a crossover exhaust. The restrictor was not removable. [without grinding tools] Not like the interstate mufflers.

    As far as I know all the aftermarket peashooters were large diameter all the way through so they are not restricted..
     
    Last edited: Nov 10, 2018
  5. Madnorton

    Madnorton VIP MEMBER

    Joined:
    Jun 9, 2008
    Quieter sample silencers have been made, but not available just yet. We have recently tested two bikes, a standard 750 and this had 46RWHp and my 850 MK3 with the quieter silencers fitted and it topped out at 48 RWHp, it is fitted with a FA head standard valves and premiers with 260 main and 19 size pilots, and experimental cam. It has masses of torque at 2500rpm and stays all the way to 5000rpm suggesting it cannot breathe enough. The dyno operator liked the way it would pick when the throttle opened started a curve at 2500rpm

    What I would be keen to see if it is out there is a dyno result from a 68-69 Commando with the early silencers fitted.
     
  6. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    If you still have the lightweight valve springs installed you might want to see what happens if you increase the spring pressure.
    Usually the only sign you will see with low spring pressure is the power goes flat early.
    The Fullauto head can easily make power past 6500 if everything else is correct.
     
    Last edited: Nov 11, 2018
  7. Madnorton

    Madnorton VIP MEMBER

    Joined:
    Jun 9, 2008
    Not so much lightweight, just light on the seat. They are standard springs, but with the lift on the cam I will need a spring with a lower rate otherwise the top end will be too high. Not sure how I can get around it, or if springs with the lower rate I would need exist. Might send a spare head up to Steve and see if he can fit larger valves, the end of the day, I want it to be a smooth road bike with a nice, but not massive increase in power.

    You just about make out the power curves here, sadly it does not show the torque, you could eat you dinner of the torque curve to go with the blue result. The fueling was the interest to Amal, mine is about right for max torque, and this is with the needle on the middle groove.

    http://amalcarb.co.uk/news/
     
  8. Esmerela

    Esmerela VIP MEMBER

    Joined:
    Jan 9, 2017
    Ashley,

    What air filter setup are you using ? I note you are using 19 pilots (a fairly recent revision to the std setting). Tony and I both run a single K&N filter on our MK3's , his is fitted with pea shooters and I use RGM's straight through balck cap reps. Both were positively asthmatic on std premier jetting, only when we got to 260 mains, richer Needles and 19 pilots and float levels set evenly, did normal service return.

    Regards

    Katherine
     
    Last edited: Nov 13, 2018
  9. Joachim

    Joachim

    Joined:
    Jan 1, 2018
    I just did a dyno run with my Commando. Then I realized that the chart format looks very similar to the original post's chart. Even the spelling of 'NORTAN' is the same :)
    Mr. Fullauto, where was yours done? I went to Russell at Dyno Time in Wangara in Western Australia. Would be nice to know for comparison.





    This is what I know about my engine:

    - 850 MkII
    - Cylinder was rebored to first oversize about 15,000km ago
    - Cylinder head overhauled about 15,000km ago
    - Original 2x Amal 932 carbs, slides sleeved
    - Pazon ignition

    The rest of the engine seems original but I never had it apart so I don't know for sure.

    Reason why I did the Dyno run is because I am about to rebuilt the engine. I am planning to do a few mods (camshaft, compression, porting etc.) so I wanted to have a before and after comparison just out of curiosity.

    The AFR chart showed that the engine runs lean up to 3000rpm, then too rich. So with the right carb adjustment I may have achieved a slightely better result.

    I am a bit surprised that my engine is relatively close to Mr. Fullautos, with the nice head and the PW3 I would have expected a bigger difference.

    Anyway, I will update in a few months when the engine work is done.
     
  10. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    If we take the two graphs as gospel, yours appears to be a touch stronger in the middle 4-4.5 rpm and Fullautos is a bit stronger at top.


    Glen
     
    Last edited: Apr 11, 2019
  11. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    Yep. Russell at Dynotime. I can't believe he still can't spell "Norton".
     
  12. Madnorton

    Madnorton VIP MEMBER

    Joined:
    Jun 9, 2008
    Here's and 850 running rich with a compression plate fitted, FA head, Premiers, plate now removed and needles dropped one notch, so most probably running a little better than what was obtained below.

    Andover Norton 2.png
     
  13. Fullauto

    Fullauto VIP MEMBER

    Joined:
    Apr 13, 2009
    Dynojets are supposed to be a bit more "generous" in their outputs than Dyno Dynamics aren't they?
     
  14. illf8ed

    illf8ed

    Joined:
    Dec 30, 2003
    Not to mention the machine...Commando. In a perfect digital world some analog eccentric is refreshing.
     
  15. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Katherine, when you say richer needles, do you mean different needles, or putting the stock needles on richer clip positions?
     
  16. Esmerela

    Esmerela VIP MEMBER

    Joined:
    Jan 9, 2017
    Hi Nigel

    Different needles: 622/278 Needle 4 Stroke special

    Regards

    Katherine
     
  17. Madnorton

    Madnorton VIP MEMBER

    Joined:
    Jun 9, 2008
    My above trace is with 'as delivered' early 850 premiers with the needle in the middle groove, as can be seen it is in tolerance but very close to being to over rich, I have since lowered the needle and the plugs are a nice light brown. Clearly there is scope with a standard carb to get it to deliver more. The cam is PW4, radiused followers and valves were standard size. The dyno tester was also impressed with the carbs response to gear changes when he was doing the run, even compared to FI systems he sees, which is nearly all the time.
     
  18. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Interesting, thanks.
     
  19. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Admittedly I have not read all the posts, but if you do have a single carbie, you will increase the bottom end rev range, meaning you will be able to ride in top gear a full 8- 10 mph lower if you fit reducing sleeves into each inlet port-don’t ask me how I know. . . .
     
  20. Hillbilly Bike

    Hillbilly Bike

    Joined:
    Oct 18, 2018
    This is very interesting reading...Looks like the Norton makes a flat torque curve but not so HP ? Has anyone had a 650 Norton on a dyno...
    Just for comparison although you cannot compare different dyno readings is my 650 Triumph..This is not a radial engine ,10.5 compression, Sifton 390 cams, Mikuni 34mm flat slides, raised intake port floors and 1-1/2 x 34 inch straight pipes...This naked frame modified production bike was timed at 133.2 MPH at the 1-1/2 mile land speed track in Loring Maine .
    The dyno is a eddy current Superflow, considered to be more conservative than the inertia Dynojet...The charts show "DJ" (Dynojet) conversion power numbers on the extreme left. The air density when tested was 1800 feet. The A/F sensor was not functioning...

    [​IMG]


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