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Discussion Starter #1
I know everybody says the Qsc kit is the best bang for a buck on the 850 xp, but would spending the extra money for the new primary be worth it? As far as performance how much better is the new primary? And which primary is best?
 

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Discussion Starter #3
Idk which primary would be best for the money I've heard good things about airdam, but idk much about them. As far as what I'm lookin for I just want more low end power but I don't wanna loose top end and I don't really want a high stall
 

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Both options will give you that. The QSC kit for $219 will net you 3+ lengths over a stock machine in 100 yards with no top end loss, stock to stock tires. The airdam/cvtech clutch at $650? is not really any gain on a well clutched Polaris. The Polaris primary clutch is what Team, QSC, and others base their design on for the other brands to convert to. IMO it's a waste of money to change out the original Polaris for another companies imitation of it. I sell a lot of QSC primary clutches to Can am guys for $840 set up with weights and spring. They are a modified Team/Polaris P85 made to fit the can am crank. They have a smaller diameter bearing in the center, vs can am or airdam, which gives a lower starting gear ratio in the clutches from a stop. In some machines, as much as 30% lower. On the Canam machines it's a huge improvement in low end and efficiency. The Canam primary is pressed together and the outer face slips on the shaft if clutched aggressively or used with big tires and high HP machines. That translates to belt slip and lost power to the wheels.

So, "bang for the buck" on a Polaris, a clutch kit is the best money. For an all out racer, it's still an eternal debate between them as to what works and what doesn't. On any given race day it seems they go back and forth and are about even. What's funny is the other brands are all using the Polaris or another similar design to it instead of the original stuff they came with.

As far as the QSC clutch kit for the 50, stall will be 1600 and is adjustable to 1800, 2000, or 2200 if you want to. But in most cases not needed. You will get smoother engagement in fwd and reverse, elimination of the reverse jump they do, more low end and mid range power and no more 0-20mph lag time before the power comes on.
 

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Ridin - what differences are there when you start looking at STM clutches? They look like works of art (with a price to match)...
 

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The stm primary is no where near as good as the Polaris imo. Not as easy tune and parts are not as available. Lots of cheap Polaris tuning stuff out there for cheap. The secondary on the other hand has its place on anything but an xp. The xp roller secondary is similar in design, and actually reacts faster. If you suck the belt down into both secondaries and then rotate them to get back to idle position, the stm will take about 10-12 full rotations. The Polaris will do it in one rotation. The secondary is what controls how your clutches shift out and back shift. Faster reaction there is better. Polaris clutches are flat out hard to improve on without sounding a ton of money.
 

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Discussion Starter #8
Thanks for the replies Ridinagain, if I can gain 3 bike lengths in 100 yards I don't see anyreason to buy the new primary. I'm not running big tires no bigger than 27's will I see the 3 bike lengths with the smaller tires? I've heard it makes alot bigger difference with big tires
 

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Bigger tires rob HP no matter the machine. That in turns takes top end and acceleration too. Clutching and clutch changes help to get the power band back where it should be, and in good design will give gains where wanted or needed. So, going to bigger tires than stock will cost you a big of performance, clutching for them will get most of it back. You may not see as big of gains on a machine with bigger tires and a clutch kit vs a stock one as you would see stock to stock, but there will be gains none the less.
 

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For what its worth, i just installed the qsc clutch kit for my 850 and i think its ok. I gained a little on low end but mid range was greatly improved as well as havimg a more "snappy". With the rake and the 30 backs it still wont pull the front end off the ground. I did not replace my belt that i have been ridimg on for a year so that should help when i do
 
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