gen 1 best fuel

[VNA]

Now here's a thought for you.

If by using an ignition advancer - which simply means the spark is provided x number of degrees earlier (the engine rotating 360 degrees) than standard.  So if this gives a you a power gain with 95 or 98 RON petrol (whichever the advancer is designed  to work with).

Then does it not follow, that if your bike's ignition is set for 92RON, and you put 95RON in, or 98RON, you will get a slight drop off in performance? (with no advancer fitted)

Surely.