The big V-twins air cooled do get hot and noisy like at thrashing machine when hot..
Syn oil helps but only a little..
When sitting the motor being air cooled does radiate heat..and of course you are sitting directly on top of this heat...
and the noise is normal...not deadened by a water jacket..but actually transmitted along the cooling fins...
An oil cooler does work when not moving...oil is still being pumped through the cooler and the heat simply leaves by radiation...movement or a fan hastens this process..
I put an oil cooler on the Harley because it was an easy and attractive location and the cooler has a thermostat which opens at 187 deg F
It does work and keeps the oil about 15-20 deg F cooler.. (I have an oil temp guage..) which only helps keep the crank area and the oil itself cooler..
Like older Harleys the oil tank is remote in the dry sump system on the R* and the oil travelling along the lines to the tank under the seat gets cooled ..more so than if the oil tank is tucked closer to the engine..
as well the oil in the R* is shared with the transmission and clutch and so larger exposed areas...and volume..keeps oil cooler..
For these reasons an oil cooler helps but is not as needed on the R*..but it does help..
Since most of the rest of the motor is air cooled the oil has little effect cooling those areas..
So living with the clatter and the heat is why the air cooled V_twin gives us the real motorcycle experience we so much enjoy..