was my only ride last fall and this summer, and served me well on my recent move back to Louisiana. two weeks later, though: grinding.
first noticed tues morning, thirty seconds from work: a grinding noise/sensation below to my left, most prevalent when not revving, when I was decelerating on engine braking. I feel like it was even slowing me down.
being outside work, I had no time to diag, and was hoping to credit the situation to my vehicle hypochondria
after work, five mile ride home in moderate traffic, it proved to be the real deal. was almost imperceptible at first, but I was revving high till i got closer to my downtown apartment.
pulled rear brakes off optimistically hoping it was just a caliper seized (happened to me before). no dice.
drained gearbox (thanks for the site, basscliff): very low, but no shavings to speak of, in the oil or the magnet. refilled, let it soak, ran in neutral some, still same problem.
drained and refilled again. this time some minute shavings came out the overfill hole, nothing that seemed extraordinary for a 30 year old bike.
checked differential oil on the shaft, was crystal clear, maybe even a little overfull.
the boot over the... ujoint? what's it called? had a tear, but inside looked clean.
ran it through gears on the center stand with no rear wheel, seemed... fine. no noises anywhere in the range.
same with the swingarm and driveshaft removed. nothing to get worried about audible, and hand on the gearbox felt no grinding.
BUT there was definite recent scoring on the front end of the swingarm, where the turning driveshaft hit, metal on metal, the swingarm. I have pics to illustrate, will post them when I can het to a desktop PC (recently in town, no internet in our place yet).
so that is superfresh, and I'd want to blame the problems on that. but... my pal thinks we can't know we didn't cause that ourselves when running it on the stand the first time... the scoring happened on the bottom side of the shaft opening, presumably because the shaft was angling too downwards. I can't contribute, I was manning controls and feeling the gearbox while he was eyeing the bearings in the differential. neither of us noticed any noises or jerking I thought we would have if we were witnessing an unrestrained swingarm getting eaten into by its driveshaft, so (maybe optimistically) I am wanting to blame my highway noises/grinding/drag on a collision of the shaft and swingarm.
but even that doesn't make total sense to me. in regular operation, how would they have touched? in the teardown, I hadn't seen anything indicating the swingarm was angled too downwards.
toss me ideas. I suspect if no-one has clues, tomorrow's steps will be taking the engine out and pulling the gearbox off. which I dread.
my pal suggest bringing my rear wheel and differential to a shop to have them inspected. i'm skeptical, I really felt the noise and grinding vibes were coming from my side, not behind me. also local dealership mechanics seem to treat their customers with (at best) mild derision.
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