Originally Posted by flying_hun
I would argue that water cooling was a big break through. It wasn't long after radiators appeared on 125's that an aircooled bike become too slow. Water cooling allowed engines to be built to generate more power because liquid did a better job of letting the engine effectively shed the heat that comes with more power. Tighter tolerances can be used by thermal expansion of dissimilar materials happens in a more controlled fashion with liquid cooling than air cooling. I still prefer the look of an aircooled motor, but power is power.
Water cooling was a hugh breakthrough. IIRC the first attempt at water cooling (~75
) was a trick head (fox, denco
) that used passive cooling i.e; the water jacket was in the head, as the water heated it would circulate to a small radiator, be cooled and returned to the head. No pump or anything