still got some air (mity-vac will solve that) or just the fluid getting hot. i know my clutch lever on the zrx gets wierd after a long ride but still seems to work perfectly fine.
could be ya need to rebuild your slave cylinder (sticking which in turn causes clutch to slip)

 

When the fluid gets warmed up all the free play is taken up and it gets to the point where you can get the clutch to slip if you accerate real hard. When I was coming back from a long trip I actually had to stop to let the thing cool down so the clutch woulkd stop slipping. After rebuilding the slave it was great for about one day and now it is back to no free play when it warms up. I was going to rebuild the master cylinder next but it still does not make sense to me.

 

I have the same issue with my 1996 vulcan 1500 when it heats up the clutch will slip. My Clymer manual says if this happens then there is air in the hydraulic system. I have two kits on order, so I can rebuild the master cylinder and the slave cylinder. Let me know if you have resolved your issue, I am curious as to what is causing it.

 

I agree - it sounds like air in the system - see if you can bleed it at the master and slave - a reverse bleed may be the best way to force the air out?