dasch wrote on 01/13/09 at 02:03:20:Oil filled gauge? Why'd they do that? Smooths the needle a bit?
Yes ,smooths the needle vibration.
At 30 deg F / -1 deg C, with 20W-50 syn "Mobil 1" motorcyles oil, the pressure can be at 60 psig at start-up. At 50 deg F / 10 deg C, it's approx 50 psig cold. Once engine is warmed up in cold weather, it's 10 psig at idle.
In hot weather, 90 deg F/ 32 deg C, start-up is around 30 psig and hot engine at idle is approx 2 psig. (yes... two ).
In cold weather , you can NOTrev the engine until it warms up. The gauge will peg the needle Yes, I should have put 10W-40 in for the winter .........