Understanding Yamaha Primary Spring Information

[zr8000]

Just purchased a 2007 Attak.
I have some of clutching experience with Arctic Cat so I have decent understanding of clutching theory.
As I investigated my stock setup, it seems I have the Y-S-Y primary spring. When I check out the Yamaha tables, I find the OEM information but see it is not evaluated like other manufacturers or even aftermarket Yamaha springs. I typically look for forces at two different compression lengths to understand characteristics.
A couple specific questions concerning my Yamaha spring.

1. How to know if sled has the 'short' or 'long' spring as defined in Yamaha primary spring chart posted in these forums?
2. How do you purchase aftermarket springs if they are rated like everyone else and Yamaha is rated using preload and rate?

 

[sideshowBob]

1] the "short" Yamaha primary springs are from the early clutches that had a lower primary over...mostly pre 1999.
2] Yamaha measures their clutch springs metrically in Kilograms...to match up with after market springs just convert kilograms to pounds. For example a Y-S-Y long spring is 35/118 that would convert to 77/260 pounds.
The easiest way is to multiply kg x 2.2 to get pounds.

 

[zr8000]

I see...thanks.
Holy smokes that initial pressure is light.
Will probably lighten that up a little bit yet so I guess i have to get used these 4 strokes!

 

[Stubbs]

Your Attak will have the "long cap" YSY Primary spring. All of the 4 strike Yammies have the longer springs. The preload # determines your engagement RPM. Yammy uses kg/mm The higher the #, the higher the engagement. Total force is also measured in kg/mm and indicates the total force required to compress the spring far enough for full shift. The higher the #, the higher your shift RPM will be, all else being equal.