06-12-2015, 01:00 PM
(06-12-2015, 09:56 AM)Flynrider_imp Wrote:(06-12-2015, 07:02 AM)Randy B_imp Wrote: The air cooled engine has something to do with it.
I suspect that the absurdly long nose is for better heat transfer from the cylinder head. Honda also put extra oil passages around the plug heads to improve cooling in that area.
Of course, my air cooled CB750 uses $5 standard sized plugs and no special oil passages for cooling, but combustion chamber temperature control was not that critical with the emission standards of 20 years ago.
I suspect that the absurdly long nose is for better heat transfer from the cylinder head. Honda also put extra oil passages around the plug heads to improve cooling in that area.
Of course, my air cooled CB750 uses $5 standard sized plugs and no special oil passages for cooling, but combustion chamber temperature control was not that critical with the emission standards of 20 years ago.
The oil was all about controlling the cylinder head temp to stabilize it for better emission regulation out of the engine. This is the only air cooled engine I have ever seen with a catalytic converter on it, and that is for a reason. The unpredictable and wide ranging head temps would make it so the converter would clog up in short order. With the oil passages in the head it helps keep things much more controlled and allows the bike to pass much tighter emission standards.
Fun stuff.