What causes a stator to fail?

Mav, Yup, the rect. circuit is simply a bridge of diodes or thysistor, reading from input to ground.in one direction(same for all legs) should be 20 ohms or less, and at least 100K w/opposite polarity.this converts ac to pulsating dc. typical output is around 15-30 vac per leg from stator at idle to as much as 200 vac (per leg) at revs. cumulitave pulsating dc is what the reg. works with. blown diode/s either drop leg/s reducing accesible voltage. or deliver ac (nullifying input) and /or allowing current to backfead from battery thru stator to ground, (draining batt.when static.) Sounds like you've been there, Quick checks for stator, all legs continuity to each other(usually an ohm or less), all above ground, output per leg (ac to ground) and when connected reasonable charge rate at batt. a quick check for blown diodes is a test light between disconnected batt. terminal and its feed, key off. (either + or - will do) a light indicates key off draw. unpluging stator will either confirm or eliminate source. hope this helps. G

MFolks wrote:

Another place to look is after the sprocket cover is removed, to inspect the wire bundle running above the engine sprocket in the channel. The side stand switch,the neutral switch and the oil pressure switch all run with the three wires from the alternator.

Heat,vibration and age can cause any of these wires to get a break in the insulation possibly reducing the alternator output or causing it to short out.

My neutral light either is completely off or when it is on it flickers. When I replaced the stator I had to change the connector, I probably should have soldered and shrink wrapped, could this be my issue with low output from the stator.

Not trying to jack the trend, but this topic is very interesting.