i am using motal 600 in both my NSR,s and both start no problem, and run just fine on it.
i also run it in my 350 yam. i had a lot of top end trouble untill i switched to motal 600, from a cheaper oil i was using.
i,ve used rock oil in a GAS GAS 330 trials outfit that got used real hard most weekends for two years, and only needed a ring when we stripped the motor.