Originally Posted by Silk
Penrite recommend their 10W-50 motorcycle oil - Penrite over spec on everything, it'd be where I would go.
I'll second that. I've been using their products in all my bikes for years, actually decades, zero problems and in fact very positive results. EG, I run several bevelhead Ducati's, and these engines use all ball and roller bearings, no plain bearings. The crankshafts have a reputation for problems as they run a roller bearing big end with ball bearing mains. Owners typically accept that the cranks will die at relatively low mileages, using Penrite, NON of the cranks in my bikes have so far needed attention.
They also have bevel gear driven shafts to drive the cams which are also sensitive to the type of oil used, again, no problems. I'm not advocating that Penrite is the only oil that works in this type of Ducati, but I've yet to hear of another that works so well, and I won't be experimenting to find out!
I'm monitoring Penrite in my Royal Enfield, which I bought new in 2018. I did the first oil change myself using Penrite, miles are low at the moment but I did notice the gearchange improved and neutral was easier to find. That could of course be due to bedding in, but I'm betting it's the heavy Zinc content that Penrite use aswell.