Originally Posted by 2008superduke
... when I measured any of the three prongs to the ground with my multi-meter I got O.L. So I guess that is an open circuit? I would imagine that it should of had some resistance? ...
That is the correct reading - the windings should
be isolated (i.e. infinite resistance or open circuit) from the core.
You will however measure a low resistance (less than 1 ohm) between each of the three pins to each other. But that is not what we are looking for in failure diagnostics.
Although the wire looks like bare copper, it in fact has a clear insulating sleeve over it.
When the actual windings fail it has burned through the insulating sleeve on the wire and shorts to adjacent turns or directly to the core.
So what we are testing for is the integrity of the insulation, rather than that of the actual conductor.
Yours certainly looks black because it has been hot in that zone and the lacquer discolours; (I think that is what you are seeing burned as opposed to the wire's insulating sleeve) but that one is probably not actually fried to failure.
This is one fundamental reason they fail, is because of the poor cooling in that region and why the fours seem to have disproportionately higher stator failure than other Triumphs. A new one will ultimately look similarly.
My recommended diagnostics for stator are quite simple:
Measure resistance (isolation) between stator output pins and engine ground
a) If short, stator is definitely bad - proceed to remove cover to validate - no need for test c.
b) If open, good indication that stator is OK and proceed to test c to validate
c) Start bike with R/R disconnected, measure the AC Volts between the three combinations of pairs of pins
All three should be very close at any given engine rpm. Idle is usually sufficient to see a problem, although if failed, a larger difference will be apparent at higher rpm.
When failed, a significantly lower voltage will be evident on one phase vs the other two.
If it passes first the isolation test and then the voltage test (all three phases show the same voltage output at any given engine rpm) then the stator is good and I would not proceed to remove the cover - you will just scare yourself with how it looks!