Motorcycle Repair: 1981 Honda CM400E tail lights not working., bikebandit com, filament bulbs

Question
I have a 1981 Honda CM400E.  The problen is that the tail lights are not running.  The lights will work if I use the turn sgnials or press the brakes, but they do not run all the time.  Is there a loose wiring harness? If it is where is it located?  Thank You Jason Fortinberry

Answer
Jason, assuming that the bike is stock and unmodified, you probably just need a new 1157 bulb. One filament is stop light and the other is tail light.

http://houseofmotorcycles.bikebandit.com/honda-motorcycle-cm400e-1981/o/m2126

The rear turn signals are generally independent of the tail and  stop light functions. The FRONT turn signals have double filament bulbs, so they are running lights when the engine is on and turn signals when selected, too. Running lights generally will go OUT when the HI beam of the headlight switch is selected.

If the bulb is known to be good, then the other cause can be a bad ground to the bulb socket. That is generally a green wire in the harness back to the light socket.

Make sure all wiring connections are clean and tight, including all ground paths.

Bill Silver