I've experienced a rattling that seems to come from the drive shaft, but I'm hoping it's nothing of concern.
I recently changed the oil in the motor, final drive and gear box. Bike (2007 1100) was on a lift. After changing the oil I briefly ran it while on the lift before double checking and adjusting the motor oil level. The rear wheel was running with no resistance of course.
There was an irregular rattling/metallic sound, somewhat like popcorn popping, which seemed to come from the drive shaft area. I've not heard this with the bike running on the road, so I'm hoping this is just because it was running on the lift with no load, and not because of my diminishing hearing while riding.
There was no issue with the oils - no filings on the magnetic drain plugs, and the oil in the final drive and gear box was clear. I've had no issues when riding of any kind, and we just finished our 7,700 km US state capitols trip with no problems.
I'd like to believe there is no issue here, but does anyone know if this rattling is the sign of a problem, or is it just what happens when the drive shaft turns with no load on it?
I took the shaft off about 2 years ago and greased all the bearings so that's already been attended to. If this rattling is normal there's no point in taking it apart again.