I've got a 1976 Honda Elsinore MT125. I bought it for $550 in July 2012, and I've slowly got it running over the past few months. So far, I have replaced the coil, the spark plugs, the rear inner tube, the carb boot, cleaned the carb and and added a flasher relay, turn signal bulbs and a brake ligh bulb. It runs and rides well, it's a blast in the corn fields, but I want to ride on the street. I have the title, I just finished the IDOT safety course, but now I need the headlight tailight brake light and horn working. The lights all work by themselves, but if the headlight and tailight are on at he same time, after a few seconds, they both go dim, and when the turn signals are flashing, the other lights flash opposite. I did a few tests, and with the taillight on, and the headlight off, I let the battery charge for 20 seconds, then turn the headlight on and turn the engine off at the same time. When it charged at 1500 rpm, the light lasted 2 seconds after the engine is off, at 3000, it lasted 5. Then I performed he same tests, but left the engine running. At 1500, the light lasted 4 seconds, and at 3k it lasted 9 seconds. I was told to start with checking the regulator. Where is it on the bike? What other problems might this be? Here
is a video showing the problem. Cheers!