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Discussion Starter #4
wow..thats quite hard to understand it haha ..but I get the gist of it.

One thing I was wondering In how do you change the engagement of your sled?

adding stronger springs?
 

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wow..thats quite hard to understand it haha ..but I get the gist of it.

One thing I was wondering In how do you change the engagement of your sled?

adding stronger springs?[/b]
Well, that's one way, or your could go with lighter shift weights (cam arms, whatever you want to call them) but in either case your shift RPM will be pushed up as well. If you do that, you shift past the powerband of the engine, and it will produce less power and also stress your crankshaft bearings. There are shims you can install next to the primary spring to fine-tune (raise slightly, like 100RPM per shim) the engagement if that's all you need, but I've found those shims will also push your shift RPM up a little as well, so be careful with that. The primary spring has an engagement pressure and a shift pressure, and there are many combinations. In my opinion the best way to raise engagement is to get a spring with a higher pretension but equal shift rate to your correct configuration (following your sled's stock clutching chart for your altitude). If you can find a primary spring that fits the bill I believe you will get the results you're looking for. If you can't find the right spring I'm sure there's companies out there that will sell you a spring and weight combo that will give you the engagement and shift RPMs that you want. Another way to raise engagement is grinding notches in the shift weights in the right place...I don't know the details on that one.

Yes it is hard to understand. Essentially the primary clutch applies the engine power to the belt and the secondary shifts gears (or allows the shifting to occur) in response to both the power applied and torque feedback from the track. Heh, so there you have it. :lookaround:
 

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[post="Go here,"]www.aaenperformance.com[/post] order Olav Aaen's Clutch Tunning Handbook, if you really want to know. Highly recomended, but be prepared to read it 2 or 3 times before it starts to make sense. :thumbsup:
 

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one thing that is a plus, a doo does not have the weights as cat and poo. they have pins in the arms that can be changed out for adjustable ones so the weight can be changed. however the spring will still serve the same function. I can see how the shim will affect the shift rpm as it is changing the pressure of the spring by compressing it a lil'. changing the rpm with the lower pin weight might cause belt slippage.
 

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basically here is how it is. for raising engament rate if your spring is lets say a 145/280 you would go to a 165/280. a change like this will raise the engament about 200RPM
 

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im confused on what you guys mean by 'shift' do the clutches really shift? I thought the faster they spin the more they close up thus making the belt spin fatser, i didnt think it shifts.
 

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thats what the shift is. you have a shift between low and high gear really. this is the time between when the primary finishes closing and the secondary is opening creating kind 2 gears. this is why tunning your secondary can make such a difference in midrange power its right at that shift point. if you fail to get full shift out of both clutches you will fail to get max acceleration and top speed and will not reach peak RPM.
 
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