Chick is right (they always are just ask them! ), the bikes (1300 and 1800 both) are both low compression engines, thus no requirement or advantage for high octane gas. You'll only get a lighter wallet. A lot of people from this area will specify 87 octane 'cause that is the lowest in this area, But if you go to places like CO , with a high altitude, the 87 octane is mid octane...there you use the 85 octane because of the thin air, if you have a 1300 and go up in the mountains where the air is even thinner, you will need to idle your motor up, even with the 85 octane 'cause your bike will be running richer than it does at lower altitude.
Chick is right (they always are just ask them! )