Duh, Dude? I was making a little (infinitesimal) joke there, Jim.
I have always used Honda's Moly 60 lube on all of my shaft drive motorcycles, however they changed their formula to a much lower moly content last year and, comparitively, that's not an acceptable product for me anymore. I'm hording 1.5 tubes of the old stuff for future applications.
Yamaha made an equivalent product to Honda's older, original formulation, but I'm not sure that their YamaLube product is the same as it was either or if it's even still available???
It appears that the Loctite product will do the job, albeit for more $$$ than Honda's formally excellent product will. One of our resident gurus, Warp 9.9, touts Krytox as the best available spline lube, but its cost is either prohibitive or unjustifiable for many folks.
Scroll down to the "Spline Lubricant" section in this link for the partial lowdown!
Motorcycle Shaft Drive Grease