I have a 76 sportster XLH. Own it since 1988. Just replaced solonoid plunger because pin sheared off on shaft. The starter would spin the clutch basket with no load (plugs out of jugs.) With the plugs installed, the starter drags. The starter gear that engages the flywheel disengages and the starter pinion gear just spins. I built a jig to hold the starter shaft in place so I could watch what is happening with the primary cover off. I don't see anything obvious. My manual doesn't have a bench test for this prestolite starter. Battery is new. Starter from 2007. Any tests I can perform on the starter to see if it is good or bad. Thought the new plunger would correct the problem, but no such luck.