I'm going to be something of a dissenting voice here. I will agree that there are thermal issues with air cooled engines, particularly when at low speed or stationary but some of the oil temperatures being bandied about here are way too low to drive off the combustion contaminants, in particular the water. Running a synthetic oil at 230 to 240F isn't so much a problem as a necessity to keep it in good condition. Running at 180F might be a good thing if you're racing and changing the oil after every meeting but on the road I wouldn't want to try for the 3000 mile change interval.
Additionally, the amount of cooling that the oil contributes versus air flow is questionable for the cylinders and heads; there's no cooling galleries around the cylinders, just fins on the outside remember. The MMC cooling fan seems to do a pretty good cooling job when it runs as programmed and, as has been pointed out before, the cowling that it fits in is very good at channelling the air flow when moving at speed around the cylinders giving more even cooling which is arguably closer to the original design assumptions for a bike engine.
Don't worry, nobody has to believe or even agree with me, and I don't even have the cooling fan on my M3W never mind an oil cooler and I live in a cooler climate than many on here. I have driven it hard in 95F conditions and it didn't seem in the least bit troubled unlike myself, I was a nasty sticky, dehydrated mess by the end of the day.
I enjoyed the read. If you want to get into an oil war, go on a v-twin site and just mention oil change or synthetic vs Dino oil. Grab some popcorn and watch the posts. These v-twins run hot. It is the nature of the beast and it doesn't surprise the engineers that designed them. However, sitting in traffic they get upset with heat and start doing all kinds of fun things! With that being said, I am only concerned about traffic situations. I know that if I.am going to do a toy run or parade ride, I take a bike with a radiator! I have read somewhere, about oil viscosity break down and the temperature where that occurs. It has been some time ago but I am thinking that doesn't start to occur until 275 degrees and up, and that was with regular Dino oil not this new synthetic oil on the market. Most of these big displacement v-twins come with oil coolers installed on the bikes now, if there is no water cooling. I guess I said all that to say this, I just want some cooling happening when I am stuck where I can't get air across the engine. Are you saying that the fan blowing on the cylinders is sufficient for cooling in stop and go city driving? I am just trying to figure it out since I do not have a temp gauge on the car
