Since there seems to be renewed interest in the '71 SS, let me share a few of my discoveries.
I'd love some feedback from others who have one.
Most Commando lovers know the most obvious differences between the other 1971 models and the SS such as the different seat, gas tank, skid plate and handlebars but maybe I should review them for the not-so-into-SS Norton nuts.
The seat for the '71 SS was different from any other Commando seat. It was shared only by the equally odd Hi-rider.
The seat had the regular stitched seams running across it, the Norton name on the back panel and the chrome bottom edge. The difference was slight but very noticeable when compared side-by-side to another model. The closest was the Roadster. The SS set had a different shape at the front end - slightly pointed but with a flat front edge. It's hard to describe but easy to see when compared. Just accept that the SS seat was different from the others.
The handlebars were absolutely unique to the SS. It was the only Commando to have braced bars. That is, there was a welded brace across the bars approximately 1/2 way from the top to the triple crown. I think this was done to achieve the look of an American scrambler. It's like today's motocross bikes.
Again the SS gas tank was different and shared only by the Hi-Rider. And again it' a bit hard to describe but easy to see when compared to say a Roadster. The tank was a bit smaller and rounder than the others and with a perfectly flat bottom. It was the only colored part of the bike and came in yellow or orange.
I should add that the tank and the seat were fiberglass - not metal.
The other obvious differences include a skid plate, unique to the SS, and a high-mounted front fender. This required a special diamond-shaped bracket and rubber mount bolts.
While the mufflers seem different, they are completely normal Norton Commando Pea-Shooters. It's the mount that's really odd.
Firstly, they are obviously high mounted like a scambler. But unlike the earlier S they split so that there is 1 muffler on each side of the bike.
I personally can't believe that people mistake the two machines since to me that difference is so obvious but it happens all the time.
I suppose it's because they've never seen an SS so call any Commando with high mufflers an S.
However, now we get to some very subtle differences.
Look closely at an SS and you'll see two thin, black fiberglass leg protectors over each muffler. These are held in place by a curving bracket at the front and a flat bracket at the back - all unique to the SS.
These leg protectors are unique to the SS - and sorely needed. I have permanent scars on my inside thighs from burns sustained while sitting on my SS. The leg protectors offer scant protection. Fortunately those scars match perfectly the scars on my right shin caused by the kick starter of my 1966 Ducati 250 Diana.
Back to the SS mufflers.
In order to maintain the Isolastic nature of the Commando, the SS mufflers required a unique mount. So there is an odd assembly of triangular plates, rubber bushings and bolts which hold the mufflers to the side engine mounts, those polished aluminum odd-shaped sort-of-diamond-like devices that all Commandos share. The method by which the SS mounts attach to the side plates is unique to the SS. It has to be seen to be appreciated. This mount BTW, is one of the most common modifications made to the SS simply because they were a pain to assembly and install. Many SS owners just drilled extra holes in the side plates (gasp!) and bolted the mufflers directly to them. Any coordinated movement between the engine and the mufflers which was required a part of the Isolastic system, was lost but it didn't seem to make much difference.
On some SS machines the headlight was the slightly smaller version but that does't seem to be consistent.
So, as an earlier post suggested, if you have all the correct parts, you can turn any 1971 Commando into an SS in less than 1 hour.
I have a complete set of Hi-Rider parts and for fun or for a display, I'll make an SS into a Hi-Rider.
That's really easy since the tank and seat are the same. Change the bars, the front fender, remove the skid plate and drop the mufflers and you have a Hi-Rider. And with appropriate serial numbers too.