2016 Grizzly clutching?

Loving my new Grizzly but have some questions for those who have put shims in. First I have a 05 673 Grizzly with a 1.5mm shim and 4 450 weights. Bike will snap and yank the wheels anything under 10mph. From a stop it will go on rack if you want it to. Second my old 09 my buddy bought is on 30’s and same mods Yanks Wheelie’s for day’s!
The new Grizzly I first tried 1.5mm and couldn’t really tell a difference. So I am now at 1.7mm and still have to yank on the bar’s to pull the front’s. Weird thing is it will pull them from 5-10mph easy? What’s going on here? I am currently running 27’s and plan to run 28-30’s. I am scared this new motor is top end only or is the tuning that limited?