in majority of cases a bad stator will be indicated by failing following test:
Check resistance from any one pin to the engine ground terminal
- this should not read any indication - maximum resistance or open-circuit.
If you read 'short' in that last test, then your stator is bad.
(if open, it is not quite
guaranteed your stator is good however - but in majority of cases a failed stator will fail this isolation test)
Check the AC voltage output
from the stator with engine running:
Leave stator disconnected from the R/R and start the engines.
With meter set to read AC Volts check
All three should be the same value - any significant difference of one reading will indicate a bad phase and the stator is probably defective.
At idle this should be ~ 20V* and rise to ~ 70V* at 5K rpm.
I hesitate to use absolute numbers here as this can be different between models and test equipment and especially the engine rpm!
What you are looking for is same value between phases and like increase on each phase as rpm increases.
If any of the above tests raises suspicion, pull the cover & inspect the stator. It is simple to do and can set your mind at ease by seeing what it looks like. Hopefully NOT with 1/3 of it a black charred mess!
If you have to replace the stator and R/R, especially because of a shorted R/R and excess current drain, be especially careful to ensure that your wiring has not been compromised. Replace any cable &/or connector plug that is not in optimum condition.
Now on to the alternative R/R replacement
When this thread first written, there really wasn't a good Series Regulator
widely available as a replacement candidate. Now there are a couple of options that are in play.
This thread is read by many non-Triumph owners so I will define the replacement strategy into two groups
1: If your bike marque/model generally has a robust stator with low failure rate amongst the population, then MOSFET Regulator remains a good reliability improvement for high-failure SCR Shunt Regulators
2. If your bike marque/model suffers from a relatively high failure rate in the general population, then MOSFET Regulator will do NOTHING to improve this situation and selection of a Series* style Regulator becomes a much better choice.
* The short version is that a Series Regulatorwill run much lower current in the stator and so it will have the stator itself producing lower dissipated power, run cooler and be more reliable.
Generally, a much better device regarding the reliability of the stator. The only downside - until recently - has been cost vs good value MOSFET Shunt units. However that 'value' is achieved if stator replacement does not have to be added to the equation!