The spark plug wire is part of the HT coil I just replaced. I have not replaced the boot on it but it was high and dry and worked for many miles until there is a hint of rain or wet roads.
There is a kill switch on the bars which I bypassed to avoid that issue. There is no kickstand kill switch.
I'm thinking it could be water getting into the flywheel/stator and shorting it out or perhaps a bad back plate on the stator.