Ken in Oklahoma wrote: When looking at the bike I would place the bike on its centerstand, in high gear, with the rear wheel elevated above the ground, and rotate the wheel back and forth. What you're looking for is slop in the whole driveline, which includes clutch and rear wheel splines as well as gear clearances and even a driveshaft spline in the final drive. I don't have an "inches-or-rotation" figure to give you. Perhaps somebody here will.
Ken
Even if the splines are good there will be variations in how closely the rear drive mesh is set up. For what it's worth Haynes says 0.15 to 0.2mm tooth back lash up to 1980 and .08 to .14mm 1981 on. You can multiply that by approx. 5 at the wheel rim. Then add back lash in the spines which would be multiplied by approx. 6 at the rim.
My 16,000 mile bike has no more than 4mm free play measured at the wheel rim so you can reasonably expect at least this much. Perhaps that is close to the good end of the spectrum for the inches rotation figure although mines a 79 so maybe the later bikes were better.
