Came across this on the YouTube today, I know I've seen several discussions about this problem on the forum. This seems like a legit solution.

Head Hoggers Bagger "Shaft Gripper" Vibranium Shifter bushing
Are you tired of that sloppy hole your (shifter) shaft runs in? Are You ready for a nice tight, smoooooth one? Well, you came to the right place! The new head Hoggers "Shaft Gripper" Vibranium shifter bushing will completely transform how your shifter feels when the bike is warmed up! Gone is...
head-hoggers-1312.myshopify.com