Dominator and Atlas ? What to look for if purchasing ?
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texasSlick
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The Featherbed framed machines are definitely the best handling machines of the era.
The Atlas is generally criticized as having too much vibration, but I think this is a bad rap. I do not think the Atlas is any worse than any other big British twin of the era. Perhaps (perhaps means it is mostly conjecture) part of the Atlas vibration can be attributed to poorly machined cam rings in the magneto, which were known to cause timing mismatch up to 25 degrees. Machinery worn out by the demands of WW2 made the bad cam rings and these would have been increasingly worse as the years progressed, culminating in the Atlas era, as the Dommies faded. My Atlas, never any worse than the contemporary 650 BSA's and Triumphs, smoothed out a little after I corrected a 6 degree timing mismatch to zero degrees. This experience leads me to believe any magneto equipped bike, Atlas or Dommie, would vibrate perceptively more with timing mismatch of 10 to 20 degrees as was commonly found in that era. Newly made cam rings are spot on, so no longer a concern, but the magneto of either machine should be properly set up to ensure a zero, or 2 degree max. timing mismatch.
The larger bore and piston mass of the Atlas vs Dommie is commonly blamed for the "bad vibes" of the Atlas. If I were a younger man, I would install JSENG lightweight pistons and Carrero rods (1/3 less mass + longer rod length). So equipped Atlas's are said to be really smooth, but not so like a Commando, but then, a Commando does not handle like an Atlas.
Slick
The Atlas is generally criticized as having too much vibration, but I think this is a bad rap. I do not think the Atlas is any worse than any other big British twin of the era. Perhaps (perhaps means it is mostly conjecture) part of the Atlas vibration can be attributed to poorly machined cam rings in the magneto, which were known to cause timing mismatch up to 25 degrees. Machinery worn out by the demands of WW2 made the bad cam rings and these would have been increasingly worse as the years progressed, culminating in the Atlas era, as the Dommies faded. My Atlas, never any worse than the contemporary 650 BSA's and Triumphs, smoothed out a little after I corrected a 6 degree timing mismatch to zero degrees. This experience leads me to believe any magneto equipped bike, Atlas or Dommie, would vibrate perceptively more with timing mismatch of 10 to 20 degrees as was commonly found in that era. Newly made cam rings are spot on, so no longer a concern, but the magneto of either machine should be properly set up to ensure a zero, or 2 degree max. timing mismatch.
The larger bore and piston mass of the Atlas vs Dommie is commonly blamed for the "bad vibes" of the Atlas. If I were a younger man, I would install JSENG lightweight pistons and Carrero rods (1/3 less mass + longer rod length). So equipped Atlas's are said to be really smooth, but not so like a Commando, but then, a Commando does not handle like an Atlas.
Slick
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Of course the best thing to look for would be a totally original running bike. I'm sure there's a few out there but good luck! I ride an Atlas and a 650SS regularly but it's not fair to compare types based on my examples since neither is completely original. Yes the Atlas vibrates more but it's still fun if you recognize Its limits and don't rev the p.... out of it. Both can be made to have very livable vibes in usable rev ranges if rebuilt with a dynamically balanced crank. It's been so long since I've ridden a Commando that any handling comparison would be meaningless, but feathered handling was certainly ahead of its time. Original drum brakes can be made decent, but leave a lot of room and have an escape route. Be suspicious of any magneto that has not been rebuilt by a reputable rebuilder. They all die from old age. They may work fine on a short test run but then leave you stranded once warmed up. EI makes for easier starting but requires associated mods to the charging system since now you need a good charge in the battery to run. Original fenders are rare and the Indian copies can be dodgy with the wrong circumference. Atlases are the bargain of the featherbed world since they got a bad rap for vibes and were more or less dumped on th US market where they were seen as sport bikes although they were intended more to be high speed tourers. The 650's, 600's and 500 twins are rare in the US. If you are seriously interested I know of two 650SS that may be for sale. One is a project and the other has been restored. HTH
texasSlick
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+1 with Bodger's caveat regarding a totally original running bike. If you consider a basket case, be certain all the major parts and bits are present. It is horribly expensive to replace missing components.
JohnnyMac has a nice Atlas in the For Sale Section.
Slick
JohnnyMac has a nice Atlas in the For Sale Section.
Slick
Yes that Atlas for sale could be a good deal. If the mag and rebuild are legit you would be ahead of the game. I have a featherbed with Excel alloy rims and they make a noticeable difference in an already good handling bike. The offer of the tank badges is real value. Go ride it!
texasSlick
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The mag on that bike may be the NOS still in a box K2F that JohnnyMac found somewhere. The rebuild amounted to a new Bright Spark capacitor. JohhnyMac's avatar is a picture of that NOS magneto. A good deal indeed!
Slick
Mags are problematic but can be corrected, always check with timing disc and bulb and battery that they fire 0 and 180 degrees. Higher compression pistons in Atlas, other that the now unobtainable 7.5 -1, will increase vibration, as I found out to my cost.
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Dominator vs Atlas depends on what you are wanting. If you are just looking for a featherbed I would get an Atlas. The Dominators, depending on the year, can take time and a lot more money to get up to par than an Atlas. Atlas parts are everywhere and later Domi's shared many of the same parts outside the power plant. Just try to find a set of useable 600 barrels then go look for pre-Commando 750 barrels and you will see what I mean. Mags done right can be costly but after that it's no longer a worry. Featherbeds are almost effortless and if I had the skill it would probably impress me even more. Can't believe Johnny still hasn't sold his.
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Jims lite 750 pistons he reports as 190gms
I own all of the following, weight with no rings or pin-
atlas dished piston 218.5 gms-
stock 750 commando 063229 piston 236 gms-
dommie/500 244 gms-
hot rod commando/atlas pistons 265 gms-several sets all similar
stock 850 pistons 289 gms-
rgm 920 pistons 303 gms
I am a very big proponent of light pistons and will be carving down the weight of at least one set of 750 high compression by as much as 40 gms for my hot rod combat/atlas
Dominator and Atlas ?
I have always tried to figure out what is? or is not a dominator?
Still never got a satisfactory answer.
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From what I have gathered from old advertisements and broshures is the Dominator line included the Model 7, 88, 99, and 650ss. Manxman and Atlas were listed under their namesake. I have read articles that included the Mercury in the Dominator line but have found no Norton published literature to support.
Dave, what have you seen or found over the years?
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Hi Scott
The only pretty sure thing is, it leaves out the rubber mounted commando.
garden gate, wideline, slimline usually in ...I have not paid much attention on the hybrids
some stop at small cylinder head NHT, so leaving out the desaxe 750 (atlas).
It does appear to be as much a marketing concept differing from a factory declaration.
The only pretty sure thing is, it leaves out the rubber mounted commando.
garden gate, wideline, slimline usually in ...I have not paid much attention on the hybrids
some stop at small cylinder head NHT, so leaving out the desaxe 750 (atlas).
It does appear to be as much a marketing concept differing from a factory declaration.
The 650SS was definitely a Dominator-based machine, but I don't remember it ever being referred to as a Dominator model. I rode one every day to my job at N-V for about a year, 45 miles each way. When we moved to about 8 miles from the Villiers works, I switched to an AJS street/scrambler prototype and the SS went back to the London factory vehicle pool. At the time I used it, the odometer was showing 130,000 miles, but I had no idea if that was real.
I emigrated a few months later and didn't keep in touch.
I emigrated a few months later and didn't keep in touch.
See attached picture of advertisement from UK "Motorcycle Mechanics" magazine for "Norton Dominator 650 Sports Special." I assume Norton registered "Dominator" as a trademark (I believe the new company has done so). A cursory search didn't turn up anything, but I'm not exactly a UK trademark expert.
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Very good...an advert comissioned by Norton factory in the day of 650SS sounds convincing enough to me. So this would make small bolt pattern heads as Domi. Domi being the engine, because the garden gate and both featherbeds were then powered by, and refered to as domi. I have plenty of ads for the model 7 being a dominator. If any one has seen atlas referred BY NORTON as domi that would make it aceptable to me.
However the recent decade fights over model names and ownership makes me accept the practical end of NORTON motorcycle with the end of rotaries. Late 80's early 90's... when I visited England several time including visiting Norton@Shenstone and RGM, fair spares(now norvil) and Hemmings and several BSA shops.
However the recent decade fights over model names and ownership makes me accept the practical end of NORTON motorcycle with the end of rotaries. Late 80's early 90's... when I visited England several time including visiting Norton@Shenstone and RGM, fair spares(now norvil) and Hemmings and several BSA shops.
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I defer to Dynodave's expertise with respect to the engineering features that correspond to the "Dominator" models. Hoever I suspect that the name doesn't appear on any drawings and was instead thought up by some anonymous copywriter. As for its abandonment around the time of the Atlas, perhaps with.the advent of the "swinging sixties" it was deemed inappropriate to use a name that could result in a female rider being referred to as .
That was a good find, Bodger. Even being an N-V employee and riding the company's "hack" 650SS for tne best part of a year, that's the first reference I've seen tying it to the "Dominator" model name. It was obviously a derivative of the smaller-engined Dominators, particularly since it had the Featherbed frame, but I don't remember a reference to the name anywhere on the bike itself.
texasSlick
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It seems like Marketing pronounced it a "Dominator", but there is no mention of the word in any of my Norton manuals.
Slick
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