Join Date: Nov 2010
Location: Mulberry, FL. USA
Main reason for the oil cooler is to remove the heat picked up in the wet clutch...Only place where oil is used for cooling in a pure motorcycle air cooled engine. I has insignificant or no impact cooling the engine, it is not its purpose..... is an oil-properties preserver, not an engine cooler. Best analogy of this oil cooler job in a car is the automatic tranmission fluid cooler, even though in a car; engine an transmission are separate.
In the 80s, japanese air cooled fours had no oil coolers in the States, but same bikes would have air coolers in Europe. The rason was; it was assumed in the more crowded, narrow, winding roads of Europe, the rider would have to shift more often and be more aggresive than in the vast expanses and straight roads of the US.
As long as you don't abuse it or go "racing", the ZN is OK without the oil cooler.
As a note; today all big retro air cooled bikes have oil coolers, and all high performance liquid cooled bikes also have them. Some times is an outside oil-to-air intercooler, often is an internal oil-to-liquid coil wrapped around the oil filter.
Last edited by Hugojose; 10-02-2016 at 08:58 AM.