We have been doing some research on the '62 Honda CR72 Prototype and have met with minimal success. It has a one off twin cam 4 valve engine with chain driven cams not gears like all of it's successors. The engine was stuffed into a CB72. Presumably this was done for testing to be sure the concept worked before going into "production". Allegedly Honda had a US serviceman race it for a short time while serving his tour in Japan. It disappeared after that. It was rumored that he brought it to the US when he returned from duty.
To date one photo has turned up and that being in a Japanese bike magazine.
The top bike is the prototype CR72 and the bottom bike is one of variations of the "production" race bike.
If you know of any pictures or information about this bike or know someone who knows someone.... your help would be greatly appreciated in helping piece together the history of this motorcycle.
Thanks in advance