Don't know if this helps - I see you already have a picture. This is the Zener, heat shield and bracket on a '64 (manufactured) 650SS. The view is over the rocker cover looking forward. NB the bracket is held by the front tank bolt and the bolt on this side is longer to allow for the thickness of the bracket. FWIW I have owned several featherbed the manufacture year '62 had the round heat sink and the '64's had the square.
atlas questions..again
- Thread starter MikeG
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Beach
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Not really sure if some came as rectangle plate or maybe made by a po. It did look like it could be original.
Round ,square rectangle, all the shapes under the sun can be used, as long as the xx square inch was there for the heat sink, later bikes had "pretty alloy cast" shapes see Triumph, BSA.
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We are discussing nortons right? My only recollection is the round discs on slimlines and then carried over to the first fastbacks like on my friends 68. I don't know when the zener dropped back to the Z plate like on my original 70 roadster. I believe the "S" had them on the Z plate. This all comes into play buying todays repop (lucas) harness offerings that I am not confident of they are any good. I have 4 series 1 commando harness' and I'm running into trouble over rectifier and zener placement.
Correct. All 1964-onwards Dommi models had the Zener under the left front tank mount. Steel bracket p/n 026656. Square aluminum sheet heat sink for Zener diode is 030042 (2 off) and spacer 030042. Heat sink, spacer and Zener diode are shared by the G15 series.
Don't confuse the Zener diode with the rectifier. The latter is fitted below the saddle.
-Knut
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Not so. AMC/N-V never made a casting for the Zener diode. It's square plates for 1964-66 and circular plates for 1967 right up to the first Commado models, as mentioned by Dave.
https://www.ebay.com/itm/Norton-fea...600455?hash=item4da4470887:g:-QIAAOSwR9NdvEXM
(032018 is the circular one, 030042 the square one.)
-Knut
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Mine was rectangle. . . . . .
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To help Dynodave, my February 69 Fastback still has the Zener & plates etc partially in behind the left side cover held in place by a rotolock I think the "R" type was the same, I would suggest that the change may have happened when the central oil tank was introduced.
I stand corrected. New information was provided by Anthony Curzon and I have changed the text above. Obviously the samples I have were of the later type.
-Knut
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That had been my assumption also. I can't say I have actually ever seen and examined a 70 fastback. I owned a yellow 70 roadster exactly like my new avatar(except girl). I'm in the midst of 2 early commando projects both central oil tank an "S" and my new 70 yellow roadster. I have been examining closely any Series 1 commandos I can find locally.
So is it generally the earlier (slimline) ones that are rectangular shape?
By 68 my atlas heat sink was round and all commando ones I have seen before going onto the z plate.
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Dave, I found DogT's write ups on this forum when restoring his '69S very informative, I was at the time building a '70 [since been sold] and he was a great help. I am currently in the process of finishing a late '66 [or early 67 - built 29th September] Atlas.
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thanks I'll search dogt posts
Good luck 67=119760+ if the books are correct
AFAIK 66 atlas are the only ones with 389/689 carb set up. I have 2 66's, 1 complete bike stock w carbs, 1 basket case as a bitza hot rod.
I was alway curious about 389 monoblocs, that there was around 150 paired variant/models but only about a dozen 389/689 model sets. Then the concentric was released....
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Thanks Dave, though my bike is about 600 numbers short of that s/n I have a NOC Records Certificate advising a manufacture date of 29 of September, it came to me with 28mm concentrics which match the inlet ports[28mm] though I have managed to buy a pair of 389/689 Monoblocs. Sorry to hijack this thread.
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I'd absolutely agree. The information coming from within USA is scarce like the general # of slimline vehicles here. While the atlas may have been targeted to the USA market after the Manxman release by the then new importer Berliner. The slimline market was pale compared to the eventual Commando market. The almost schizophrenic pace of model "upgrades" and changes makes nortons quite challenging to keep up with technical and model evolution.
Just as an example I own 4 slimlines and 16 commandos. Commando research is relatively easy but NHT slimlines are a tougher subject. I feel sorry for the wideline people here in the USA.
To bad you refuse to be part of the New England Norton Owners, this also serves me well being able to call and talk to owners willing to help or show their hardware/machines. The local British bike meets are great also for doing research.
http://www.britishmcmeet.com/britishmeet/index.html
MikeG
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Two more questions then:
I see that the original heat sink was 2 aluminum sheets that look to be 3 inches in diameter with a spacer in between?
Any harm in using one thicker sheet of aluminum rather than the 2 thinner ones?
I was a member for several years Dave but due to work scheduling I was only ever able to attend one meeting. My membership expired a few years ago and I don't think I ever got any kind of notification that it did. A poor excuse I know, but it's the only one I got. I did attend the meet in Bolton last year, and will go again this year.
I see that the original heat sink was 2 aluminum sheets that look to be 3 inches in diameter with a spacer in between?
Any harm in using one thicker sheet of aluminum rather than the 2 thinner ones?
I was a member for several years Dave but due to work scheduling I was only ever able to attend one meeting. My membership expired a few years ago and I don't think I ever got any kind of notification that it did. A poor excuse I know, but it's the only one I got. I did attend the meet in Bolton last year, and will go again this year.
Beach
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The 2 sheets give more surface area to dissipate heat. So a single piece would not work as well.
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It's never to late to sign back up! Going to a meeting is quite anticlimactic.
I am listed as the NENO tech contact and I do get occasional calls for help.
If your not getting the club news letter you will not hear about the april "Start Your Engines" cook out and dyno day.
Super simple physics, 2 sheets of metal have twice the surface area of one piece. There would be a small and thin copper thermal carrier in between the two plates. Silicone thermal grease on assembly prevents corrosion which kills the thermal path. A proper heat sink assures the zener lasts longer than you and me put together...
Yeah Bill beat me to the enter buttom
I am listed as the NENO tech contact and I do get occasional calls for help.
If your not getting the club news letter you will not hear about the april "Start Your Engines" cook out and dyno day.
Super simple physics, 2 sheets of metal have twice the surface area of one piece. There would be a small and thin copper thermal carrier in between the two plates. Silicone thermal grease on assembly prevents corrosion which kills the thermal path. A proper heat sink assures the zener lasts longer than you and me put together...
Yeah Bill beat me to the enter buttom
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The large bracket looks like a steering yoke stop for a featherbed frame. It bolts to the plate between the two downtubes at the top. The bottom trees bump against it at full lock.I know one of these brackets is for the Zener diode heat sink, but I don't know where it goes or what the other bracket is:
Any help greatly appreciated....again. I can't believe how little info is out there for the Atlas compared to a Commando or BSA.
