The bottom curve of these graphs is a light-throttle acceleration. The stiff clutch spring has the clutch locking at ALMOST the same RPM (5500rpm) as the lighter 6g rollers begin to change gearing(5800rpm).
**If the springs are too stiff (or maybe clutch pads worn), or the rollers are too light(or variator has a very low starting gear), then the variator COULD begin to shift gearing before the clutch locks. This could result in worse acceleration, excessive clutch slippage, and premature clutch pad wear.
****Add an aftermarket variator into this mix of changes, and the stiff clutch springs may NOT be a good change for many scooter owners.****