here we go.
Those are great pics. Other than the first one though..the others look like they may have been photoshopped???
Agree with 754..seems what we knew as "choppers" came out mainly in the late 40's 50"s (when I started riding)..we called "bobbers" @ the time. A lot of the old WW ll surplus bikes were "bobbed"..to get lighter..more maneuverable around city streets..etc.
A very common "bob job" was to take the back half of hinged rear fenders off of Harley's..add a bobbing ornament to the fender end..strip the front fender off to bare springer fork..take all the guts (speedo..gauges) out of tank center..add simple toggle switches in place..add riser bars (maybe)..respoke front wheel to smaller tire size..put on a cool set of chrome pipes..etc. That was though the late 50's.
Then in 60's seemed like folks had more disposable income..folks like Big Daddy Roth..et al.. started getting very creative..and what we recognize as true choppers today..were more or less born.
Today..still think the V-Twins look very cool chopped..but my heart's been with Honda/the in-line 4's pretty much since they came out in the late 60's chopped or stock (also have soft spot for Ariel Square Fours chopped..which I had BTW...but are/were not comparable to the Honda's in terms of reliability..etc.). Much refer to ride stock looking bikes nowadays BTW.
Ichi