Hi,
I assume that the three designations you mean are "Dual Twin" "Hurricane Scrambler" and "SR".
The Dual Twin was the roadster model with exhausts mounted low down on each side, plain unbraced handlebars and a full length front mudguard (fender).
The Hurricane was a Street Scrambler version with high-mounted pipes with heat shields, braced handlebars and an abbreviated front fender.
There were a few other small detail differences, but the pipes and fender were the main visual ones. Also bear in mind that as the basic bikes were the same, it is quite possible that a Dual Twin could heve been fitted with Hurricane exhausts, or vice versa. There is no way of telling how the bike started life.
The 175"SR was a factory tuned racer, distinguishable by having black expansion box exhausts ending under the seat, a single seat and smaller fuel tank (basically a BS90 item with two taps fitted). Oh - and the SR came without all the trappng of a road bike such as lights and speedo. THe 175 SR is also exceedingly rare these days.
There were later 200cc bikes - the "Mach II" roadster and Street Scrambler which were simply 175 bikes
bored out to 200cc, and fitted with a separate speedo in a pod above the top fork crown. The 175s had the speedo mounted in thw headlamp shell.
Probably your best move is to check out pictures in the Gallery section of this website. There are numerous pics of all models there which shouild allow you to identify what you have when the bike arrives.
Good luck, the small BS twin is a nice bike to ride.
Graham
