Chains break even more than belts. This is why everyone switched over. With chains one has to keep it clean and lubed. Inside the M3W rear, it gets astonishingly filthy in short order.
Not sure the bit about breakages is true. I have seen one chain break on a racer at Prescott, but it's not a common complaint.
However, the power of the five speed engine would dictate a larger chain and it's a very messy way to transmit power. Just about any maintenance task on the back end is a filthy job, and it needs to be kept clean, lubricated, and adjusted. Not the sort of job that would attract folk I think. So I can understand Morgan's logic.
