2010 Sportster with a Champion trike kit... I've developed a whine/whistling sound when accelerating in any gear. No noise at idle... nice and quiet. No noise when putting into gear and taking off. The noise starts when accelerating in any gear. The noise is RPM related, not speed related... meaning it increases as the RPMs increase, then repeats when you shift gears. The clutch operates fine... no slipping, no rough feeling... engages and disengages smoothly.
I changed the primary fluid today and checked the primary chain tension plus adjusted the clutch... made no difference. Primary chain tension was fine, and the drive belt tension is fine. There was no significant extra metal shavings on the drain plug magnet and no shavings in the tranny fluid. The bike is a 2010 1200 Custom with 14,000 miles and has had Amsoil 20W50 in the primary since 1,000 miles.
My fear is that it's the clutch bearing starting to make noise. Any other ideas what it might be?