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Discussion Starter #1
Hi all. Been a lot of discussion on clutch kits, what they do, how they work, are they worth it, etc. So to help explain a little I'm throwing up some pictures of a couple weights to compare and explain how they work. Weights effect the way a clutch engages, how it shifts out and what RPM they run on top. They are bolted in through the hole you see in them and sit at idle just above the hole. As RPM goes up, centrifugal force forces them to want to point out instead of into the center. The shape of the ramp on top and the distribution of the weight along it effects how it works.

First picture is the overall difference between a stock 63g Polaris weight that comes in an 2012 850 and the 60g QSC weight that goes into their typical 850 kit. As you can see they are very different in basic design, yet accomplish a similar task, only in a slightly different manner.

Second is the difference in the ramp profile. You can see at the base by the hole that the Polaris one has kind of a hump there. That hump is what causes the harsh and higher RPM engagement on the XP line. You see the QSC weight is much smoother and softer transition there. That is what allows it to start moving at a lower RPM and engage smoother and softer. When the stock weights "pop" past that hump they slightly over-shift the primary a bit and cause that lazy bottom end that I hear everyone complain about while the engine overcomes the sudden extra load. The smooth transition stops that.

Third is the difference in weight distribution. You can see the stock weight as mostly based at the heel, near the pin. The QSC weight has much more middle and tip weight distributed along it's length. More weight in those areas is what gives these kits the low and mid range punch that everyone seems to love about them. They also get a much stiffer primary spring on the finish rate end as it is needed to help keep the weights from grabbing the belt to hard and dragging top RPM down. The heavier tip does lose a bit of top end, but helps with a quicker backshift as well for that power that you need coming off the corners on the trail. As with all things CVT there is some give and take throughout the range to get what you want out of it. You get a whole bunch of smooooth bottom end and mid range power and give up a few MPH on top to get it.

Keep in mind the sportsman line is really designed and built to be a work horse, not a high spirited trail machine that we all want them to be. However, with the right parts in your clutches you can certainly make a huge step in getting it there!

Hopefully that helps explain a little bit to everyone and minimize some of the new threads and constant questions on what a kit will do for you.
 

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Discussion Starter #4
Just grabbed set and took some. They are much more similar. And not surprisingly. I believe Adam started designing his clutch kits to work with the 850 he races and expanded to the value lines form there. The QSC looks to have a little bit more low end and tip weight, but very minimal. However, everyone that I have talked to says there is a noticeable enhancement in the low and mid even over the 10 series weights.
 

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The ramp looks to have much more aggressive upshift right off the bottom. That is just what I need. I think this may help me with my overrev down low.
 

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Awesome thread Ridinagain!
I'm coming off of years of sport and race quads. I know them inside and out and do all my builds myself. These auto clutches are all foreign to me. Every bit helps in understanding.

I am so excited to buy a clutch kit from you come late winter. Will be getting some new tires and maybe wheels then doing a clutch upgrade at that point. I have a friend with a Raptor 700 that needs to be put in check. lol
 

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Found a very general video on the CVT operation. It doesn't discuss the inner parts, but it helped me get a better understanding.

 

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I created a PDF with all the pages for people who want to save a single file and print it.

Thought it could come in handy.

It's in my shared folder on my google drive.

Here is the link.

https://docs.google.com/folder/d/0B5EMXmE75LIJcVNmYkM5aGhSZWs/edit?usp=sharing
Here is another outline of CVT operations including the weights position and operation. (Its a sticky in this section. http://www.polarisatvforums.com/forums/atv-performance-modifications/20841-cvt-clutching-101-a.html)

CW
 

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Does the secondary on the quads move in and out also??

Sent from my SGH-I337M using Tapatalk
 

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gotta remember thu the stock Polaris secondary is set up for those flat profile stock weights with no tip weight that is why they use a reverse cut helix
if all you are doing is putting in a primary spring and weights with the stock secondary you will as a few guys said can develop a dead spot in the clutching, which will recover but sucks when riding on a no slip surface, to put up with that hesitation, especially when you are racing your buddy and he pulls 2 lengths on you when your clutches are arguing with each other what to do until your secondary backshifts for a second and off you go, but I understand nobody gonna spend 600 or 700$ for a complete clutch kit. Ryan keep up the good work on the very affordable HP to the ground Kit
 

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Would changing the secondary spring eliminate that?

Sent from my SGH-I337M using Tapatalk
 

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So a clutch kit should really help the first (2/3) of the drive run while leaving the last (1/3) up high alone. What does that large round thing with 4 "peaks" do? Looks like it goes int he secondary or something.
 

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Discussion Starter #15
So a clutch kit should really help the first (2/3) of the drive run while leaving the last (1/3) up high alone. What does that large round thing with 4 "peaks" do? Looks like it goes int he secondary or something.
That thing is the helix. It has ramps cut at specific angles that the rollers or buttons in the secondary (depending on clutch style) ride on as it shifts in and out. Those angles ,along with the spring, determine how fast or slow the secondary shifts open and closed based on the torque load it sense through the driveline.

The simple answer is you can fine tune one area of your clutching with a single component, but a big change like tires or performance adders requires a complete rethink of your clutching.

It's just like a truck, you don't take a truck with a 3:43 rear end and stock tires, throw a set of 44s on it and expect the same performance. You regear it for the tire size. Same principal here.
 
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