That question has probably been asked in other contexts, but here it's a 750cc air-cooled twin. Mostly splash lubrication, part of the system is pressurized, just enough to add a spin-on filter and an oil cooler. The original sump capacity was about two quarts, the cooler added almost a quart, which is most of the reason I installed it. A roughly 50% increase in oil capacity can't be a bad thing when the bike is being run hard.
Manufacturer calls for 20w-50, which seems to work well. In this case I've got Motul 3000 4T which so far seems to hold together real well. If I don't run that it's the Valvoline 20w-50 V-Twin formula. The manufacturer recommended OCI is short, 2,500 km, so no synthetic.
My question is this -- at 70 degrees ambient after about a half hour of low-speed in-town riding the crankcase surface temp (F) is 170, head temp around 215, the oil going to the cooler is about 155, returning from the cooler is around 135. That's about what I'd expect from this cooler.
I don't know much about how multi-viscosity oil works. I do know that above a certain temperature every 20 degree increase cuts the oil life in half, that came from the factory school when I was working as a mechanic. I don't remember the temp, but I do remember it was pretty hot and only a concern in high ambient temps or severe service.
Before now I don't know if I'd ever thought about oil being too cool. Is that a concern? Is there such a thing as an ideal minimum operating temperature for 20w-50 oil in an air-cooled engine?
Manufacturer calls for 20w-50, which seems to work well. In this case I've got Motul 3000 4T which so far seems to hold together real well. If I don't run that it's the Valvoline 20w-50 V-Twin formula. The manufacturer recommended OCI is short, 2,500 km, so no synthetic.
My question is this -- at 70 degrees ambient after about a half hour of low-speed in-town riding the crankcase surface temp (F) is 170, head temp around 215, the oil going to the cooler is about 155, returning from the cooler is around 135. That's about what I'd expect from this cooler.
I don't know much about how multi-viscosity oil works. I do know that above a certain temperature every 20 degree increase cuts the oil life in half, that came from the factory school when I was working as a mechanic. I don't remember the temp, but I do remember it was pretty hot and only a concern in high ambient temps or severe service.
Before now I don't know if I'd ever thought about oil being too cool. Is that a concern? Is there such a thing as an ideal minimum operating temperature for 20w-50 oil in an air-cooled engine?
