UPDATE and WARNING: You will likely fry your controller. Just read the comments about people who have tried this. Only attempt this with a scooter you don’t care if it fries or not.
I acquired a razor scooter off of craigslist for $35 dollars from a fellow who said it worked great. Brought it home, twisted the throttle, and then nothing happened. Figured the battery was dead, charged it and then still nothing. I googled the instructions only to learn that it won’t start unless you ‘kick start’ by getting the scooter moving 3-5 mph at first. What? That’s not how an electric scooter/motorcycle ought to work. Safety? I don’t think so, because my kid has his leg way out behind him when the motor kicks in causing him to almost wipe out (only way he can get it going fast enough with his little legs). It’s easy enough to fix though. Disconnect the yellow wire from inside the controller and re-solder it as shown in the picture. Then it works just fine. Twist the throttle and away it goes. I found the spot on the board by listening to the relays as they ‘clicked’ together when twisting the throttle.
UPDATE: I don’t know why it does not work for so many people. I took a couple of more pictures and a video. I cannot emphasize enough that before you solder or make the modification, grab a voltmeter and do the test before modding it. Take the voltmeter and put the positive end on the place you want to solder and the negative end on the ground of the battery. Have a second person twist the throttle. The voltage should go from 0 volts to 24 volts. When you release the throttle the voltage should drop back down to 0 volts. If it doesn’t you have the wrong spot. It could be my razor is an older version and the newer ones don’t have the same thing. I am not sure.
For solder I use the a 60/40 mix because the other types of lead free solder are too brittle.
I use something like this on Amazon: Click Here to See Solder on Amazon.