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Pre '64 Atlas's

Discussion in 'Other Norton Motorcycles' started by texasSlick, Apr 5, 2018.

  1. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    The first Atlas's were delivered to the US in 1962. I had a '62, it had one monoblock carb, and was rated 52 hp. I considered its performance on the "sluggish" side, and I doubted the 52 hp was real.

    Did any '62 models come with dual monoblocks? What year were dual monoblocks first fitted?

    Berliners' sales literature boasted the '63 had 60 hp. How real is that?

    What changed with the '64 model other than dual clocks?

    Slick
     
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  2. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    I thought my single carb 1965 Atlas was a bit sluggish too, but what do you expect with an engine that has those dished 7.5 – 1 pistons and can drop down to pulling away from 15mph in top gear?

    I tuned mine up to twin carbs and 10.5:1 pistons to release some power, but it wasn’t a better bike to ride around a traffic jam.
     
    Last edited: Apr 6, 2018
  3. gory

    gory

    Joined:
    Sep 15, 2010
  4. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    I regularly ride a '62 with a single monobloc and a magneto (not converted to electronic ignition). It's a rorty fun ride and not too vibratory if you keep it in the rev range where it's obviously happiest. I have no idea what the actual power is, nor do I care. Relative to almost everything else on the road in '62 it's fast. Common sense dictates that advertised horsepower numbers were always adjusted upwards to promote sales. Has anyone ever seen a contemporary review where they put any bike on the dyno? A publication that did that would have lost an advertiser. A host of modestly priced modern bikes will blow it into the weeds -but so what.
     
  5. Gilesy

    Gilesy

    Joined:
    Aug 27, 2017
    I have a 1962 Atlas. It was exported from Bracebridge street to Scotts Garage in South Africa. When I got it shortly after it had returned home 3 years ago, it had twin monoblocs. It never seemed to go that well and was a bugger to start when it was warm. I have since rebuilt engine, a lot of work on the head and frame done by Norman White. It now has a single Mikuni and goes like a dream. To be fair I didn't spend a lot of time trying to make it go better with the monoblocs, I did try a new pair I had but it still didn't seem that great. As with any bike that old it's difficult to tell how original the condition. This one certainly had replacement mudguards and Sparx ignition but externally seemed pretty unmolested. The inside of the engine was a different story. My only dilemma is whether to take the Atlas or my 750S to Spain for the Piston rally in September.
     
  6. robs ss

    robs ss VIP MEMBER

    Joined:
    Aug 16, 2016
    Slick
    Not sure about the carbs for the Atlas but...
    My '64 650ss still has the speedo sunk into the headlight (consistent with the brochure for that year). The tacho was an option, on a bracket mounted off the top fork nut (RH?)
    I don't believe (could be wrong) that the twin, external clocks were introduced until 66-67.
    Cheers
    Rob
     
  7. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    All Atlas models produced with AMC at Plumstead as of late 1963 had twin external gauges, identical to G/N15 models. External gauges was a selling point obviously.
    The 650SS was a downgraded model and as such had the speedo in the h/l shell. From model year 1967 on the 650SS had twin external gauges as well. The Mercury model reverted to the previous fitment for model year 1969.

    -Knut
     
  8. triumph2

    triumph2

    Joined:
    Aug 13, 2008
    What size Mikuni did you use?
     
  9. Gilesy

    Gilesy

    Joined:
    Aug 27, 2017
    A VM34 from Motocarb. They also supplied the manifold. Relating to the above posts my bike has the speedo in the headlamp. It also has the bronze tacho drive which leans forward. The drive cable runs very close to the exhaust, does any one have the same problem? I think the larger diameter pipes may be a slightly different shape.
     
  10. triumph2

    triumph2

    Joined:
    Aug 13, 2008
    Thanks mate. Now I'm curious as to whether the manifold is the same as the Commando or is there a difference in the angle of the faces?
     
  11. Gilesy

    Gilesy

    Joined:
    Aug 27, 2017
    triumph2 likes this.
  12. frankdamp

    frankdamp

    Joined:
    Oct 7, 2005
    Knut:

    It was my understanding that the Atlas replaced the 650SS in the model line-up and didn't appear until maybe 1964 or '65. There was very little difference between the two models other than the engine size and the paint color. The company-provided 650SS I rode for my commute in '67/68 had the headlamp-mounted speedometer. It had 130,000 miles on the clock, so I'd think it was maybe 5 years old and may have been the prototype. I don't recall it having an RPM indicator.
     
  13. Gilesy

    Gilesy

    Joined:
    Aug 27, 2017
    As I understand it, the Atlas was first produced in 1962 but for export only, it was not available in the UK until 1964.
     
  14. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004


    ....And the 650SS continued on to 1967/68. Replaced by the single carb 650 Mercury.

    https://www.nortonownersclub.org/models/heavy-twins
     
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