Try adjusting the clutch per the manual at the clutch plates under the derby cover. If that doesn't help then it's time for some new clutch plates.
Current bikes in the stable:
2009 Street Glide
- 107ci, stage III heads, D&D Fatcat exhaust, Andrews 54 cam, TTS, 108hp 122tq
2003 Heritage Softail Classic
- 95ci, stage III heads, RB LSR exhaust, S&S 510 cams, 100hp 102tq