If you're replacing your friction plates or steel plates, you might as well replace the springs while you're in there. Measure your existing ones to see if they're out of spec. If you've made all the external adjustments and your clutch still won't engage/disengage properly your springs might be worn out.
EBC springs are 15% stiffer than the stock springs.
Diameter = 19.5mm
Length = 35.75mm
Includes 6 springs - 4 to 6 are necessary per bike. Discard the extra 2 springs if you have a 4 spring clutch.