Everybody forgets that if you read the manual for all modern Trials Bikes the Minimum RON recommended for any Bike is 98RON. Hence if you are using standard Unleaded (95RON), you are losing out!! This is because the engine is set to run with this octane or better. As a rule most European car Engines are set at 95 Octane. However Volkswagen FSI and Japanese units run "Knock Sensors" which ajdjust the ignition for the higher rated RON fuels. As a Guide My 2 litre Lancer Estate does about 270 miles on a tank of 95 RON. On 99RON it does another 20-30 miles. Engine response is also better.
Because the Fuel "burns" at a higher Temp it also burns off carbon in the cylinder.