I've read an enormous amount of information about 4 stroke fuel now. I've read articles that show scientific proof why less oil is better and different articles why 4 strokes need more oil. On the Wildcat website, they explain that 4-strokes need more oil than 2 strokes...but their 4 stroke fuel only has 15-16%. There is a fuel FAQ running around somewhere on the Internet that explains that 4 strokes need less oil....because the same oil is in the engine longer. My conclusion is that no one really knows. So I'm giving up on that question.

Now, my question is what is better in a 4-stroke. Castor or Synth.?

The Wildcat website says 100% synth.
YS must think Synth because they recommend the 20/20 which seems to be 100% synth.
My engine says a mixture of both are best.

How can there be so much disagreement? Does noone know the answer to this question either?