1 - CD175 was not part of Road Master Family infact it was originally part of CA160 Dream family
2 - CD185 TWIN was not a Road Master it was a model named 'TWIN'.
3 - Only CD200 Was the Road Master.
4 - There latest incarnation is a CB250 NIGHTHawk/CMX 250 Rebel/CA250 Cruiser Rebel
As I see 185 can be your best choice, it has the power output better then 200 and if you replace its magnettor set with CD200 or a lateset CB250 its a power pack I have been enjoying it a lot with cb250 magnetto for a long while...