You could be right about a diryt connector, Did you solder the yellow stator wires or still the bullet plugs? They have been known to cause poor charging MAke sure all your grounds are clean and tight. Look for any corosion at the R/R plug. Do you have a volt gague on the bike when you ride? Good idea so you can watch it and know what is normal. 13.5 is not bad, Do you have any accessory's on the bike (Radio, Driving lights) That might be draning more than should. Other than that just general safty inspections.
Chad Falstad "Hawk"
2011 HD Ultra Classic "angel"
2001 Nomad 1500 Sold March 2012
2001 VN 750 "Sold June with 2008 with 21,000""Serinity"