There is no need to even buy premium. Just read your owners manual it tells you exactly what to put in it and I believe in my Polaris and my Yamaha it calls for an 89 octane rating, it may have even been 86.

 

When people say run good gas they mean run sunoco or something like that not some cheap 7/11 stuff

 

the owners manuel for my 400EX says 91 octane or better. i have put 87 in it and i even put 100 in it and premium 93 is the best of all, like they say the 100 is a waste of money i just tried it to see for myself and the 93 has quicker pickup as far as when i stab the throttle than 87 does.