I'm sure there's enough opinion on this issue to feed a major food fight better than the one in Animal House, phintz, but most motorcycle oils have all the proper nutrients/lubricants the 912s love and the Rotax folks will tell you the same thing. I've been using Honda GN4, 20w50 motorcycle oil in my 912UL for over 13 years and have a scrupulously clean engine interior to show for it.

Most of us in Arizona run 20w50 because of the high desert air temperatures year round along with a 50/50 mix of our favorite aluminum-engine-grade coolant from the aviation experts at PEP BOYS (red stuff or green stuff doesn't seem to matter) and DISTILLED water. Use only distilled water when mixing with coolant.

I'm sure more of our regular contributors will chime in with their favorites; use what those in your climate zone recommend, but the Honda GN4 has been superb. I'm not familiar with HP4, but it's probably the same stuff with a "New-for-2014" name. I'll no doubt find out at my next oil change!

"E.T."