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Belts

Brock

Well-Known Member
Messages
2,044
Location
Ontario
Country
Canada
Years Snowmobiling
30+
Snowmobile
Polaris
When I get bored, I measure and check things out ,lol
I did some measuring of the primary and secondary out of the machine at full shift out in primary and secondary.
Center to center is supposed to be 10.625".
Put the clutches in vises and clamped primary tight at full shift out. Opened secondary to 1.1" full shift out. Put belt in and stretched with straps on several different belts and lengths then measured center to center distance. This will duplicate what's in the sled +/- 2%.
I also reinstalled clutches and measured .
I've come up with a perfect belt measurement in circumference and pitch. Other savy techs agree .
45"-45 1/8" in circumference
43 11/16"-43 13/16" pitch length.
Anything more or less will affect full shift out.
 
So, the Gates CF 46C4387 is supposed to be 43.87" pitch length if I'm not mistaken....so, that would be to long correct?
 
What it's supposed to be and is , is two different things. Most gates belts I measure are shorter then the pitch number you mentioned.
 
Now, this is provided that the center to center distance in the sled is close to 10.625"
It's usually a little bigger cuz motor moves back when under load . So when stationary it's more then 10.625" on mist I've measured. (0.030"-0.060") more .

Since the gates belt is a little wider then the Polaris(about 0.030"), it can be a 1/16" longer and work fine
 
Yes.
It's the pitch length that counts. You can't measure around belt with a tape .
Since the gates is about 0.030" wider it may make it seem shorter installed.

Measure pitch length only and the formula I provided if you like.

If the gates belt installed is tight after track and belt warm up and doesn't give the proper deflection and sits to low in secondary. It may be to short .
Some early gates belts were short.
 


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