Here is a interesting chart to let you know how the temperture increase affects your oil. This is just for regular oil. Not synthetics or blends.

 

Who put that chart out?

 

I forget exactly where I found this chart, but it was a few years back when I was doing some extensive studying on oils. I think it was part of a big research guide I read that showed testing of oils for V-twins and all of the results.

 

I also have seen this somewhere in the past, maybe not the same but close to it.

 

One major reason I use synthetic oil.