This family of engines were Kawasaki's first liquid cooled engines, Kawasaki knew they had to be very reliable and bulletproof to help them convince the aircooled kawasaki diehards and to capture market share off some of the other brands' new, exploding liquid cooled engines.
The GTR engine is also ridiculously under stressed in these bikes, 150 hp would not be hard to get out of one if you had the money.

Regards, Andrew.

 Vstrom is gone, on the hunt for a GTR.