I assumed my headlight looked dim at idle due to the poor voltage regulation on these small bikes. We don't want the bulbs to explode when hitting well over 6v at high engine RPM. So the bulbs are built for higher volts, then look a little dim at idle. I don't ride after dark so I only see mine during daylight hours. Mandatory headlights on here in Minnesota. But check voltage at the socket vs. battery volts. Maybe you have a weak connection somewhere.