How simple to copy but improve the basic design by adding a ***king big oil pump. Is the crank on ball races? Without an obvious end feed to the crank, how does the the big end get its oil, assuming the journals are still plain?
GB I'd say it represents a step in progress of the then Japanese philosophy of copy, improve the design, cut the costs, market worldwide. The engineering of Japanes bikes was never crude in concept, but I agree that some finished parts on Japanese Machines lacked the attention to detail of European products. My Honda 50 engine was an extremely sophisticated design compared to say a Villiers two stroke, but the Honda cam wheel was a simple stamping, as were other parts you would normally expect to be machined. So this cut a cost, then add similar savings together and with volume production on a scale for a world wide market made the products more affordable. The downside was throwaway engineering, best get a new bike as economic repair is impossible, as I found sourcing Yamaha bits in the 1980's.
Swarfy.