My Theory

Growing up in Canada in the 1990s means that I wasn't alive when Norton Dominators and Triumph Bonnevilles roamed the streets. Therefore, all the information I have about either one is from external sources. The Triton was born from mating a Triumph 650 pre-unit engine (most likely the earliest versions were T110s) with a Norton (wideline) Featherbed frame. Up until the release of the 650SS, the Norton Dominator Featherbed series consisted of the Model 88 (500cc) and the Model 99 (600cc), which produced about 31 hp, so it seems no wonder why these weak engines were swapped for the superior Triumphs.

But once Norton produced the 650SS along with the new "slimline" version of the Featherbed frame, I imagine there was minimal performance gain from the engine swap, but that the prestige of the Triton had already been solidified, leading many a young man to continue the switch for reasons other than performance alone.

In the case of the Atlas, which was originally named the "750SS," the rumour is that the increased displacement caused excessive vibration. I spoke to Brian Chrichton, an editor of Classic Bike Magazine who owns an Atlas, about the vibrations. He said that his bike actually vibrates less than some other 650 twins that he's ridden throughout the years. I'm of the opinion that the "excessive" vibrations of the Norton Atlas were exaggerated, a mis-understanding that fueled the hasty transformation from Atlas and 650SS to Triton. But we shall see.