Speaking of airflow...when it comes to oil coolers, airflow is everything.
After finding the highest oil temperature my bike sustained without a front fender, I decided today to test a drilled fender. I drilled as many holes as I could, while still trying to maintain the structural integrity of the fender.
After mounting this fender, I actually removed it, and drilled more holes on the outside edges.
Then I went for a ride on the freeway. Riding at 75-80 mph for about 30 miles, my oil temperature reached a high of 279 degrees.
This oil temperature was 24 degrees higher than the 255 degrees I observed riding under similar conditions without a front fender, and I consider it unacceptable.
If I didn't fully understand before, I certainly understand now. Maximum airflow is the key to keeping oil temperatures lowest.
Althought the drilled fender looks well ventilated, it is undoubtedly more than 50 percent blocked.
Here are a few photographs of my bike after the freeway run.
I decided this was my final
ride with this drilled front fender.
After I arrived home, I cut a large square out of the fender, and installed some 1/4-inch, galvanized hardware cloth. I'll post a photograph of the modified fender later.
The next time weather permits, I am going to make another freeway run, and this time I expect the high oil temperature will be much closer to 255 degrees than 279 degrees.