Any help would be appreciated. I have a 2003 Kawasaki STX 900. When starting the bad battery warning light flashes. Warning light does go off after starting, and jet ski runs perfectly. I have read many forums and purchased a service manual (accidently got 2004) but still not sure the root problem. I'm thinking it the charging system but not sure. It does gets harder to start the longer I'm at the lake.

This is the data I have collected.
Using brand new Yuasa Battery purchased from Kawasaki Dealer
Battery Voltage on full charge 12.5 volts
Battery voltage while cranking 11.3 volts
Battery Voltage while running 13.4 volts
Charging coil output test results
brown to brown at idle 70volts
brown to brown at 6000rpm 100volts+
brown to brown resistance .9 ohms
Regulator test results
I have a four terminals (upper left,upper right, lower left, lower right)
+upper left to -upper right (open)
+upper left to -lower left (open)
+upper left to -lower right (12.5 Kohms)
+upper right to -upper left (open)
+upper right to -lower left (open)
+upper right to -lower right (12.5 Kohms)
+lower left to -upper left (12.7 Kohms)
+lower left to -upper right (12.4 Kohms)
+lower left to -lower right (18.5 Kohms)
+lower right to -upper left (open)
+lower right to -upper right (open)
+lower right to -lower right (32.2 Kohms)
Pick up coil or Crank shaft position sensor result
blue to green showed open circuit

Ok my question is based on this results and my service manual (which is for a 2004 not a 2003)I would need to replace my crank shaft position sensor and voltage regulator. But do I? Does the crank shaft sensor or voltage regulator have anything to do with charging battery and only charging the battery (remember outside of bad battery warning light, jet ski runs great)? Do the values for the voltage regulator above indicate bad regulator? Are my battery test results normal for good battery?

Thanks in advance