Everyone is hitting the nail on the head, the money saving between 87 and 91 is not but $1 per fill in a 4 gal tank, but the performance and mileage will make a diff. But if nothing else is avail but 87, it burns. E10 fuel sucks, E15 is even worse. It helps to run some cleaner through your tank from time to time to help clean out all that his fuel leaves behind, any of them will do, ie, Techron, Mystery Oil, Seafoam etc. GK13, the larger screen is great for comfort, bad for mpg, but the trade off can be worth it. Smooth throttle and stopping is the best practice. K&N filters, not worth it in my book, there was a day when I would argue that but not any more, NOT WORTH THE MONEY! Sliders, as I understand, help the performance of the scoot and may help with mpg but not by much, and the added performance will burn the fuel due to a heavy wrist, the vairator only closes so much, slides effect the area between open and closed not the limits, but a great add on to boost performance! Octane prevents pre-ignition of fuel, pre-ignition is cause by high operating temps and the compression ratio of the engine. Higher compression engines ran hard cause higher oper temps that required higher octane to help prevent pre-ignition (engine knock/pinging), So, increased mpg, dont hold your breath but "it could happen", better running scoot, could be! For a few pennies, why not!!
