loss of power on take off

I had my clutch off testing some shims out, now i have no power at take off or even in Lo at take off. i did 1.7mm of shim at the most and thought it was too much and was causing it to slip. I removed all shims and put it back to stock. It barely makes it up my ramp in Lo now. However once i get up to maybe 25 mph it runs like it's suppose to. still has great top end and all. Would running the bolts into the secondary weaken the spring and would this cause this issue? I can't figure out what it could be... the belt was fine, i got the primary nut tightened down to where i can see some of the splines before the threads... like how it looked when first taken apart. I didn't take the primary apart, only messed with shims. It feels like the belt isnt being allowed to ride down at the bottom of the primary or is slipping. it just bogs down until it gets up to speed and then it hauls like normal. any ideas on what i can do to remedy this?