Originally Posted by Shibby!
I would still like to argue the engine is still a race, or high performance engine. It was a robust design for robust racing, but it's not made to do miles. If it were you'd have an engine much like the XR, DR, DRZ, and KLR, etc. It's a robust high performance engine and through good engineering and robust design capable of doing higher milleage, but at the same time not designed for it.
By using that criteria, the XR600R was a race engine too? It was also a successful Baja racebike, and the 650R is essentially a liquid cooled version of a similar format (without RFVC).
Yet the GB500, NX650/Dominator, XR650L, etc all used the same basic engine. There were differences in tuning, but the basics were the same - and the GB500 WAS design as a streetgoing machine - and I'll be 80% of the XR650L's out there are used on pavement more than offroad.