Ritter v4.0

FWIW I ran Motul 15w50 300v in my old M96 race engine (with original IMS bearing) and short gearbox. After over 150 hrs racing in Deep South (read; 80-95F most of the time) running both sprints and enduros, when the engine was torn down there was virtually no signs of wear. Rebuilder was really shocked. BTW IMS bearing was also fine lol. We changed oil frequently and cut open the oil filter to inspect for bits but it was always clean.

We now run it in the Cup but it's 10w40 300v. Also run Motul gear oil and brake fluid (see disclaimer below). But as Dave says YMMV.

Disclaimer- though sponsored by Motul, we chose the oil before getting sponsorship. It's not the only good race oil out there, but it is very good.