I had a vague sense of this in my head, but when I actually saw the numbers…
There’s quite a difference, I thought to myself.
I noticed a difference between the head and the lower end.
I installed oil temperature sensors in two locations.
• Head cover oil passage
• Crankcase left side oil passage
I haven’t done rigorous measurements yet, but as expected, the head side runs hotter. The difference from the crankcase side can reach nearly 10 degrees at its maximum.
Naturally, when the oil cooler isn’t getting any airflow, both readings are similar.
Without riding wind hitting it, making the oil cooler larger won’t be very effective.
What I found pretty scary is that I occasionally hear stories of oil temperatures hitting 120, 130, or 140 degrees.
The head-side temperature will be even higher than those figures, so it’s wise to build in a bigger safety margin than you might assume.
High oil temperature alone won’t cause sudden failure, but running continuously or intermittently at high oil temperatures isn’t good.
As we head into the hot season, conditions will become even more demanding.
If possible, rather than idling to lower oil temperature, it’s more effective to keep it from rising in the first place—give it a try! (*’ω’*)
