Ring ding ding ! A terrific bike to go hunting bigger bikes through the twisties back in the late sixties and seventies - until Kawasaki released the Mach 111..
The H1's first model year was 69' so I believe it came a year or two before the R5 which is the predecessor to the RD. Just say'in but your basically correct. Then again the R5 and RD's were a vastly lighter, better balanced, handling and stopping bikes compared the H1's and even the H2's. It stands to reason with the right rider on the right roads Those RD's were quite capable.
Start big and work your way down, if you're premixing, do 32:1. Don't use ethanol fuel. Don't forget to adjust your needle position if needed. Carb tuning is not something you can just look up for an exact answer, you have to do it yourself in the end. Every bike is different, especially when it's not stock, and it depends on what elevation you're at too.
