It is possible to have the front "U" joint failing. They do not fail often, but it is not heard of. Since the sensations change when pulling in the clutch and unloading the drive train, this could be a place to check.
Or drive splines in the wheel getting worn out?A big plus 1 on the drive splines on the hub. 63k is more then enough miles to cause it. Many on here have had to replace the hub spline, mine went S @ 70k.
HEY you're toothless.
I can use some advice on the repair of the existing joint or replacement source. Thanks.
-Rich
>>>SNIP<<< but I've noticed that at low speed, say 25mph or so, if I zig-zag very quickly with the clutch pulled in, I get a feeling from the back end like a thump-clip-clip-pat-pat-pat-pat, almost like I'm doing this on knobbies.
Rear tyre is an Avon Azzaro. I'm thinking it's the treads that are making that feeling, as I've had the wheel bearings checked, and they're fine, as are the swingarm bearings.
Is it definately cupping as you describe it or the tyre starting to square off? Never known a rear to cup in all the years I've run the Azaro rear but IMO squaring off can give you the same feeling.