Snowmobile World banner

Pin  weight

2051 Views 6 Replies 5 Participants Last post by  mr670
I believe the set-up I'm using could use more pin weight, It's laying down on the top end.
Currently have a 200/320 with 16.5 pins pulls 8000rpm. Here is a  example, if I add more weight say 20gr pin ( will lose rpm ) So I go to a 200/350  to get back to 8000rpm.
Will there be a gain with the heavier pin's?? Both set-up's will pull target RPM.
I know there is a lot of good clutch tuner's on this board, any opinion's on this.
1 - 7 of 7 Posts
This is an interesting question. I'm certainly not even close to being an expert here, but it would seem to me that the product of the belt side force produced by the weights and the opposing force of the spring would be equal in both cases.
If you add more weight, the thing shifts out faster, lowering RPM in the process. The spring opposes this force and therefore a higher spring force will tend to prevent the sheaves from closing, thus raising RPM. If this is indeed the case, I wonder if backshifting, brought on by the torque (load) sensing secondary would be the thing that was affected significantly. I really want to hear what knowlegeable people have to say about this as it's been a lingering question of mine as well. Sorry I couldn't help.

This is one of those cat and mice topics.  With some ramps alot of pin weight with alot of spring works very well.  With other ramps little pin with little spring works.  It really is a matter of tuning prefrence.  On the 700's I prefer a heavier spring with added pin weight but only with a certain ramp.  On the 800 I like soft springs with little pinweight and a certain ramp.  Your best bet is to try it and see what you like.  To complicate matters is the secondary, this will determine how much of that spring and pin weight actually see's the belt.  A rule of thumb is 1 gram=200rpm, and 20lbs on the finish = 100 rpm.

I have often wondered about that myself. He is my thought. I chose the second setup. Even though the peak rpm is same, I reason that the heavier pin has more influence on the belt squeese during the  shift cycle. ...Mid range were the spring isn't fully compressed.  
See less See more
I know that the backshift will suffer with the heavier pin.
mr670: My sled stock was solid pin (16.5gr) 200-320 spring I went 17.9 gr pins and 200-350 and it was two to three lengths faster in the same distance,both with 286 ramps. Dino
Thank's Dino ,thats what i wanted to hear, going to try the heavier pins with the 200/350. I have been using  295ramps.  I also have a set of 286 to try.
Thanks GLracing on the insight on pin wight vs ramp profile.
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.