...but new bikes too ? I wish there was a common denominator here like the voltage regulator, bad grounding, something, anything. I end up looking at my volt gauge more than any other instrument when riding and have almost run out of gas a couple of times doing it especially as the miles get longer from my home based motorcycle trailer. I flew home one trip and immediately drove back over 22 hours straight to finish the trip in the truck while leaving the bike and trailer in a members barn to be picked up later.
Why too many variables to say for sure. I just know that any time I've personally dealt with a bike that had repetitive stator or regulator failures that further digging eventually found bad cabling, connections, looseness or the other part (stator or regulator) also being an abetting factor.
These charging systems are ok. That's not to say they are robust. Doesn't take much of a weak point somewhere to cause problems elsewhere.