Splicing a new spline end on to a pinion shaft is very exacting work. It cannot be out of kilter by the merest fraction of a millimeter. The only guy I know of in the whole bimmer community that does this on a routine basis is a guy named Bruno, whom I have heard has been ill of late and not working.
Good point.
But I have another problem now. The bike is skipping badly in second gear. It didn't do that on my first tentative rides, but I took it out this morning intending to ride to the coast, but anything but the most gentle acceleration in 2nd made it skip-clunk.
My initial research tells me this means find a gearbox on ebay. But it wasn't doing this last week, even when I was riding in a 'sporting' manner, and I did just pull the gear box and sparingly lubed the input spline. Could I have screwed something up on reassembly? (I'm usually a decent wrench, but the suddenness of this problem has me doubting)
It also smokes quite a bit on startup, even though I religiously park it on it's center stand. The devil on my shoulder is telling me this particular example may just be worn out.