Take off the front wheel and look at the speedo sender on the right side of the wheel. The pickup has 2 metal prong thingies that match 2 grooves in the hub. They made the sender ( the bit inside the hub of the wheel ) out of plastic for some reason. If the pickup prongs are not precisely aligned with the grooves the speedo will work for a short while until the pickup is done chewing up the sender ( do not ask me how I know
) If water got into the pickup and froze it could have chewed up your sender as well.
