QuadBoss Clutch Kit
Coming from the old Rhino to the RZR the handling and power difference was huge to say the least but like about every other power hungry nut out I am always looking for ways to make more usable power and better handling. With that said I have been looking at clutch kits to help make the power of the RZR more usable. Some people have a misconception on clutch kits in that they think a clutch kit makes more power because a good tuned kit makes the bike feel more responsive and more powerful but this isn't true, a good clutch kit makes the power the bike already has more usable so it feels more powerful and more responsive. No clutch setup is perfect for every individuals needs, how you ride, the tires you run, and the trails you ride on can help you decide which setup will work best for you. With my setup I have 27" Dirt Commanders which measure in at about 26.5" tall so I picked up two different clutch kits. I picked up the QuadBoss stock tire kit and the QuadBoss 27-28" tire kit so I could try both kits and tune my kit to my setup and riding style.
In the stock tire kit was a white primary spring, green secondary spring and 66 weights. In the second kit which was a 27-28" tire kit was a white primary spring, green secondary spring, and 64 weights. Only difference between the two kits was the weights.
I tried both kits and they both, for an instance, offered a much improved hard launch but almost immediately they caused my bike to shut down on hard launch, I assume because the rpm would jump so fast the bike was either hitting the rev limiter for an instance or the ECU was shutting the bike down thinking the belt was slipping. After a little research I found The weight of the primary spring decided the engagement rpm, stock engagement was around 15-1700 and with both QuadBoss kits as supplied engagement was 25-2700 rpm (white spring). For my style of riding (Trail Riding) I felt the high engagement of the kits was to high so I decided I wanted something between the two. The high engagement RPM and really aggressive launch with the white primary spring setup might work better for someone who rides a lot of thick mud with bigger tires but for my bike and riding style I felt it was a little to aggressive.
After trying both kits I did a little more research and then went to EPI to check the options and weights of their primary springs then eventually decided on and ordered an EPI silver primary spring. With my setup now (silver primary, green secondary, and 66 weights) clutch engagement is around 19-2100rpm which gives a really good launch with no ECU shut down. On the trails clutch engagement is noticeably a little higher and the throttle is a little more responsive down low which is exactly what I was looking for. The new clutch setup gives a harder launch than stock with more wheel spin and a much better feel.
In conclusion the stock tire kit with the silver primary spring substitution offers a great response and a lot better low end feel. From a 30+ full throttle punch I can't tell much difference but the gain down low is very noticeable. If you are into deep mud and need a really aggressive launch with a high stall the original kit setup with white primary spring may work better for you or you may prefer an even stiffer spring for an even more aggressive launch. Like I said before every bike and rider is a little different so don't be afraid to play with the springs a little to get your clutch setup to suit your needs best.