The mix ratio of oil to fuel is dependent upon the oil. Sure back in the 60's we used to run 20:1 with standard motor oil, not even a specialized two stroke oil. As previously stated the new synthetic two stroke oils are used at a much leaner ratio than ever believed possible back in the 60's (commonly in the 30:1 to 40:1 range). Buy a bottle of Yamalube and use their recommended mix ratio. They say 40:1 but many will run it a bit fatter at 32:1 with good results.
As far as octane rating of your fuel, you don't need to get fancy with high octane unless the bike is pinging (from pre-ignition). Even then it won't run much cooler, the higher octane burns slower more than cooler.
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