This motorcycle has replaced battery, Rectifier, alternator coils failed to solve the problem. Start the car, measuring the battery voltage, no upward trend at about 13V, pull the magneto output three yellow lines, measuring AC voltage at idle about 20V, seemed normal, but both yellow cables hit has only a weak spark, with 35W/12V lamp test, stepped on the gas barely illuminated, indicating insufficient power. Measuring coil correctly, take the iron-free, take magneto not feel magnetic force down, but new rotors put on a trial run, idle 35W/12V the light is very bright, and reassembled the charging voltage is 14V, bright lights voltage does not drop.