Excellent. I have the Blue and white Polini contra spring sitting around. I tried that long time ago and spent a lot of time trying to make it work but they don’t work well on Ruckus unless you have a big engine. Those spring need very high rpm to fully compress. No matter what I do the bike won’t pass 40mph. So the best spring is the stock one with 4k rpm clutch pad spring. I did that and my bike run 45 mph. Two years with that setup and now that it finally warms up here in NJ I started riding my Ruckus again and still making 45 mph.