Re: '79 cb750k Battery keeps dying!!

Posted by sgtslag on Apr 25, 2012; 4:05pm
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/79-cb750k-Battery-keeps-dying-tp3936906p3938711.html

One issue is that you let it idle for a looonnnggg time:  30 minutes...  When the engine is turning less than 2,000 RPM, the alternator will not put out enough energy to charge the battery; the ignition system, as well as everything else, will run off the battery, draining it (starting the engine will drain the battery of a large amount of stored charge; then the headlight, alone, will draw ~4.6 Amps, plus the ignition system firing the pistons, and you have a heavy drain on the battery, which gains nothing from the Alternator at 1,000 RPM -- normal idling speed).

Visit the Home page of this site, and download the FSM (Factory Service Manual) for testing procedures for the Rectifier/Regulator, as well as the Alternator.  Cheers!