Originally Posted By: JTK
NH73- Because it's Amsoil and it's fancy.
Seriously though. It's without side/side comparisons with ZT2800s under exact operating conditions using different oils. We'll never know.
I would think it could be comparable to Mobil 1 V-Twin Motorcycle oil or Valvoline VR-1 Synthetic, but we will never know if we can't even compare specs. Overall, consider 15w50 full synthetic better than the 20w50 conventional recommendation.