by MSW » Wed May 07, 2008 2:13 pm
Well, a battery definitely can lose a charge from sitting for a long period, but if it starts the bike and the bike runs fine for a while before cutting out, it's probably not the battery (or even if the battery now has zero charge, it probably wasn't the original problem).
The most likely culprit does seem to be the regulator/rectifier. I would think that, if it was a faulty coil or CDI box, it might kill the spark, but wouldn't kill the battery or prevent the other electrics from functioning (but this is a guy who knows little about electrics in general talking).
HOWEVER, since the bike's been sitting for a while, before I order a new reg/rec, I would go through and make sure all of the electrical connections are good (clean, no corrosion, no frayed wires or loose connections). I haven't ever heard that the rectifier fails at an abnormally high rate on these bikes, nor have I heard that they fail more frequently after having sat for some time.
And as you know (to paraphrase Neil Young), corrosion never sleeps.
EDIT: To say that I don't have any idea what the specs are on the Yamaha XT regulator/rectifier, but it sure does look a whole lot different than the Baggy's. You might have to get the MZ-specific reg/rec, if necessary (even more reason to go through every single connection before opening the checkbook).
MSW
2005 Black Panther
I like my beer like I like my women: cold, dark, and bitter.