Hello fellow riders. I've been searching the forums and have found situations similar to mine but not quite the same.
I have a 2007 Road Glide with 73,000 miles. I've had it for 11 months now. I'm having a problem where the starter motor cranks slowly. Here's the specifics:
+This seems to only happen once every 2-3 months
+Sometimes, while slow cranking, the starter will pick up speed and start
+Battery and voltage regulator have been replaced under my ownership
+Stator checks out ok
+Battery voltage, including during times of slow crank, has been around 12.86V
I've cleaned the battery cables and the grounds
+The only thing I find suspicious is the voltage drops to 9.2 sometimes when cranking, which seems to be low.

Could the new battery be bad? Anything I'm forgetting to check? Thanks!

 

any thing under 10v cranking is suspect. have the battery load tested. make sure it is charged and do two back to back load tests, the first is to remove surface charge.
then there is the starter. perhaps an inspection of the brushes is in order and a inspection of the armature. the segment insulators should be below the commutator. the bearings in good shape. you could run an amp draw test. battery has the right rating? the starter relay and the solenoid contacts are also suspects, especially the solenoid contacts.