This may sound stupid, but what are the benefits of installing Dr.Pulley OD weights? How do they work?
Springs and weights offer resistance and force. Where the spring in the driven clutch requires a certain amount to force to overcome the resistance it has depending on it's setting or clocking, to effect shift-out or parting of the sheaves, the primary or drive clutch generates that force derived from centrifugal effect of spinning weights. The weight of those weights (or in this case rollers or sliders) determines how much force it will generate at a given RPM. So...its all part of clutch tuning. This is important to overcome things like extra weight, larger tires, altitude, types of riding...ect. To answer your question in a short way, a lighter weight in the primary will require the engine to be run at a higher RPM to generate the same force as it did with heavier weights. This and other tuning will help place the engine in or closer to the RPM where it develops the best power or torque for the needed performance. And using sliders over the rollers will allow a wider range of movement of that primary to give you a little lower ratio at starting and a little more closing on the top end which increases the ratio and adds top end. It's not a lot..but every little but counts. Hope this helps.