You're fine with that viscosity, it's in the service manual.
The main thing re: viscosity is what the bearing clearances were designed for, and since 50w is listed in the manual, Kawasaki's engineers seems to think it's ok.
The main thing re: viscosity is what the bearing clearances were designed for, and since 50w is listed in the manual, Kawasaki's engineers seems to think it's ok.