On my BMW R65, the issue with the drive splines was wicked.
I HAD to do it every year, no matter how little mileage that I put on the bike, or I had trouble. Sometimes I ended up doing it twice a year. If it didn't do it that often, the splines on the clutch disc went bad, and would strand me on the roadside, and need a flatbed to get it home.
I owned that bike for about 5 years, and had the tranny out more often than I changed spark plugs.
I got pretty good at it after awhile.
Of course, it was E-start only, and the thing would never start.
Everything that I had to buy for it cost a nut and a half too.
Finally got rid of the piece of trash.
I will NEVER EVER buy another BMW.
Any bike that I can't keep running, with a lifetime of being a mechanic and owner of all different kinds of European machinery, must really really suck.
My "supposedly unreliable" exotic Ducati, Laverda, and Benelli motorcycles, with all the "bad rap" about how "unreliable" they are, were paragons of reliability, compared to that stinking Beemer.
My Bullet is 1000% more reliable than that Beemer.