@Nash : I have seen CB 180 & CB 125 in single Cylinder, but I haven't seen any CB 175 in single cylinder plus I couldn't find any reference on net, that ever Honda produced a CB 175 in single Piston type.
Both share the same 'K3' and 'K7' type 'Parallel Twin' Engine, thats what I found...
correct me if I am wrong ?
Reference for CB 175 :
Honda CB175 - Wikipedia, the free encyclopedia
1971 Honda CB 175 specifications and pictures
Reference for CD 175 :
Honda CD175 - Wikipedia, the free encyclopedia
1976 Honda CD 175 specifications and pictures