Riding the bike home from work yesterday in the darkening evening when I noticed the low beam was not operational. Pulled up behind a car and noticed no brightness, but I checked at the front of the bike to verify the smaller wattage bulb at the bottom worked, as did the high beam. Thus, I'm assuming I just need to replace the bulb. What's the bulb number I need to get. It's not in the owners manual from what I could find.