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Discussion Starter #1
If I have a set up that just sticks at 9200 from full throttle off the line. How do I adjust the clutching to go to 8800 when I nail it and build to the 9200 I desire to be at. It is bad not to build RPM? Do I want a slight over rev - maybe going to 9300 dropping to 9000 and build to 9200. (all example numbers). Is there a way to tell, besides experience, when the clutches are shifting, maybe I am just not seeing the RPM build? Thanks.
 

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As long as it's not a TRA primary, I can help you.LOL
First off, you don't want to over rev. In fact, it is best to keep the engine loaded a little in most cases, so keep it on or just below what they recommend for rpm with your sled and pipes.
How to adjust your rpm? That all depends on what sled you have and what style clutches you are running. With MOST sleds if you have your clutching pretty much where you want it and are just trying to fine tune your rpms, then your best bet is to send your primary clutch weights in to someone that knows how to shave and notch your weights to your desired rpm. You can also make some very small changes(about 50 rpm per hole)in your secondary if you are using an arctic cat secondary. Where your secondary spring attaches to your cover you will see, I think, 7 holes where the spring goes in. Depending on which hole you put it in, it will adjust roughly 50rpm on the top end with the middle hole being your starting point, or 0. This is all assuming you have an arctic cat.
With the weights, they can shave a small amount of weight from the tip to increase your top end rpm. In your case you would have to add weight to the tip to drop top end rpm and shave some from the end of the weight for your midrange. The notch at the base of the weight is an engagement notch that allows you to get higher rpms before the clutch engages and helps with hole shot.
You also want to MAKE SURE that you get your tach calibrated before you start tuning your sled to the tachometer as they are usualy off considerably.
Also, post what sled you have. Makes it easier to help because my luck it is a TRA, which I have proven to know nothing about, and this is all just a bunch of typing practice for me!!haha
 

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mjwills - What kind of sled are we talking here?

All sleds will over-rev, as this is just a basic finction of the clutching. WHen the belt is shifted up in the primary and down in the 2ndary as far as it will go, then the motor will begin to gain RPM. This will most likely depend on your gearing wheather it will over rev or not.

SKi Doo usually overgears their sleds, and will usually not over rev until they are geared down. They do this to keep the belt from shifting all the way and saving on belt life.

If your sled shoulf shift @ 8800 RPM, you want to engage then actually run 8900 or so for a split second and then drop to 8800RPM all the way thru the shift of the clutches.

Example: Our asphault sled turns 9100 Rpm.

It engages at 4600 RPM and we puch the gas. At about 30ft out, the primary is shifting and the motor is at about 9200RPM, by 60ft it has fallen back down to 9100 (peak torque) and will pull that all the way down the track. At about 1100 ft. (a 100 from the end of the track) we actually run out of gear, and the motor starts to over rev, and the RPMs creep up to about 9300 (peak HP) at the end of the track.

It is how the sytem works, use it to your advantage!!!
 

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Discussion Starter #6
Sorry, it is for a Arctic Cat. Specifically a 96 zrt 600. But I was jsut looking for the general knowledge for any AC. Thanks again.
 

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There are two ways you can drop some rpm #1 add more weight or a softer primary spring. Testing will tell which set up is the beat for your sled.
The Clutch Tuning Handbok by Olav Aaen is not a bad read, not to much on t.r.a.
 

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If you want to keeep the same engagment, but run less PM, then you will change to a softer spring.
 

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Discussion Starter #10
I was using example numbers but in the end they are close to what I am running. I have AAEN pipes on a 96 zrt 600. The dyno sheets say may HP is 9300-9500. I have talked to AAEN several times about the high r's but he says they need to be there - that is where HIS pipes make their power. That get to my question that torque is usually 200-400 r's lower than HP. So I was considering playing with the clutching to peak at the torque numbers and build to the HP numbers. But I guess if I am in the band the whole time, I should just leave it alone. Or should I? Thanks.
 
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I just think that rpm is too high for a stock motor, I would hate to see it blow.
 

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Discussion Starter #12
ARCTICZRT600
I was also concerned about this. After talking with AAEN and a couple other performance dealers they agree that the stock zrt 600 motor can be safely revved to over 10,000 w/o mods. I have been running this rpm for 3 years now w/o a problem and the sled runs great. I just have time to tune because I picked up another sled. Just to be safe I did have a top end put in it at 3800 miles.
 
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