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I was installing my Dakota kit and when I changed the helix, I took the driven apart and it had 4 shims. I thought it was suppose to have three ? Does anyone know ? It shows three on the microfiche.
 

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As many as required to achieve 1"-1.25" belt deflection. If the belt is tight & it does'nt drag down the idle or spin the track excessively when in the air then your right on.
 

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I removed 1 thick shim and 1 thin shim to get deflection set properly. Has 1 thick shim and 1 thin shim left in it. My belt is 47 3/4", don't know c to c.
 

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Funny you should ask. I put a Dakota clutch on my F7 and was warned to remove the thin shim on the driven or get belt slip (I had only three, two thicker than the third. I removerd the thin one) That was good advice; my sled absolutely rips now. What's more, I just get back from Paradise and get an email from Black Magic about clutching. Here's the info:

Belt Length-----Always Important

While riding and continuing our testing on the new F7, we are continuously going back to our original setups to verify our gains and/or losses in performance. A couple of weeks ago we went back to our "baseline", if you will, only to find that we had lost a ton of performance. The RPM levels were slightly off, but the actual performance was way down. Our times in 1000 feet had dropped by 2 to 3 tenths from our original testing with the stock baseline.

Where had all of this performance gone? With all the talk of engine seizures etc. with the F7, we presumed we had inadvertently hurt the cylinder or pistons on the vehicle. We immediately checked the level of compression, verified the condition of the pistons and found nothing wrong.

We then went to the clutching system to see if we had any real problems. While the belt appeared to be a bit loose, it did not look to be the source of our problem. The drive and driven clutches were removed and thoroughly checked out, with nothing appearing to be out of order.

The sled was reassembled and tested again. Same results, slower than a toad and just not right. So just to make sure everything was correct, we took an .030 shim out of the driven clutch to make the belt work like a belt that was shorter. We went out for a ride and presto, instant performance like it was before. The rate of acceleration was back, the level of RPM was proper, and all in all, our little rocket ship was now working properly again.

So the moral of the story, never overlook the simple things. Performance on a snowmobile comes with making sure everything is working as designed. There is no such thing as a magic wand to make them fast, only TLC and the constant attempt to produce perfection.
 

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Take the clutch off. Then unbolt the 3 nuts...watch out for the spring...anyway, pull the halves apart, then remove whatever.. Make sure to put the halves back together the same way....(balance) not hard, just take apart and put together the same way...take your time..call me if you have any ?'s while doing it...whenever..
 

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My belt rides flush with the top of the secondary clutch. Is this the best setup or should it ride slightly above the clutch like on my polaris'? If it is supposed to ride high, what areas of performance will be affected by making the adjustment?
 

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BOKMAN MINE WAS THE SAME JUST EVEN WITH THE TOP OF THE SECONDARY. TOOK OUT ONE LARGE SHIM AND A HUGE PERFORMANCE INCREASE. NOW IT STICKS UP JUST A HAIR ABOVE THE CLUTCH.
 

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Yes took one small shim out, but now the belt has 300 miles on it, i think i am going to put small one back in and take out one big one.
Skydog
 
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