The speed is controlled by the OBC. You will need to take it to or have a Yamaha service agent change it. A IPalm & Yamaha programe are used through a infered device. If you lift the seat you will see where the plug is located. There are a possible of 25 speed settings available, ranging from slow with max regen. braking to max speed with no regen. braking. Make sure u have good batteries though, those 12v batteries are always causing problems where 1 will fail. Hope this is of help.