FWIW, heres a link to their ball bearing viscosity shear test of motorcycle oils. An interesting side-note to this, is that other oil manufacturers do not use this test method but a rep for Amsoil has said that the oil companies represented in this test have not contested the findings. You decide :
White Paper - A Study of Motorcycle Oils
Cliff notes :
Suzuki oil did fair, at best, in this test.
Penzoil Motorcycle Oil and Mobil Racing 4T oil did better.