The bike: '96 R11RT, 37,000 miles. Two years and 3000 miles ago I put in a new clutch, had the tranny rebuilt by Rubber Chicken, did a spline lube. I've had the bike for nine years and 15,000 miles.
Late last fall I started hearing a sort of rumbling or groaning noise coming from the final drive area. It sounded something like gears with too much backlash or like agricultural flotation tires on pavement. It wasn't loud but I could hear it. Everything seemed to check out ok, everything tight, no grumbly feeling when rotating the tire, no excessive backlash. Today the noise got louder. Still, things feel tight enough. I drained the final drive lube. There was no metal on the magnet. However; the normally clear red Spectro full synthetic 75w/90 was black. I'm wondering if there is a sealed bearing that's not so sealed anymore and contaminating my oil? There is no play at the wheel so I suspect the pinion bearing.
So, my questions to the group: Have I lost a bearing seal? Would that cause the noise?
Thanks in advance.