[Vincent]

My general observations with shims vs Coop45 machined sheave. Hopefully this will help others understand the effects these mods have on their machines before making their decision on what mod is best for them. Results may vary based on numerous variables. Belt and sheave condition greatly influences the final numbers.

Stock
2.45:1 initial CVT ratio

-1mm shim
2.65 to 2.70:1
Aprox 8-10% reduction in initial ratio, around 2.5 mph top speed loss

-1.5mm shim
2.75 to 2.8:1
Aprox 12-14% ratio reduction, around 4 mph top speed loss

-Coop45 sheave, no shim
2.9:1
Aprox 18.5% ratio reduction, equivalent to 2mm of shims but no top speed loss

-Coop45 sheave, with 0.5mm shim
3:1
Aprox 22.5% ratio reduction, equivalent to 2.5mm worth of shims but with only 1.25 mph top speed loss.



Anyone else feel free to post your own results

 

[Primethious]

Here is a great video about sheaves.
Unfortunately the Coop45 sheave wasn't compared, and I couldn't find any tech on it on youtube.

 

[Vincent]

Thanks for posting.

Did you ever compare your stock cvt ratio to your JBS kit's ratio? It be interesting to compare information

 

[Primethious]

I didn't even think about doing an A/B when I did the work.
The bike was so very new and I hadn't even gone over half throttle.
Even with that though you could tell there was a very noticeable change in the machines nature.
It went from more tractor like to something more aggressive.

 

[Vincent]

So I'm servicing my CVT after a hard 2000miles on my machined sheave. Noticed alot of evidence of rubbing on the belt and cover. Commun on these low ratio clutch set ups. They simply wear in and never cause problems. Did a ratio count and I'm at Crazy low 3.175 to 1!!!!! Remember stock is about 2.45 :1 so I'm starting at 29.5% lower initial ratio then stock! Amazing! All because as the belt wears your initial ratios drop in the favour of torque multiplication. Notice how the belt cords ride well above the edge of the secondary sheave at 3.175: 1 initial ratio....

Disassemble cleaned, greased everything and shes all back together, with my used better fresher belt.

Also note that I'm real redneck simple and only use a strap to hold my clutch while I loosen the nut with my breaker bar. I've often read impacts are hard on your one way bearing and can damage them. So I nolonger practice that method. And I always use a torque wrench to tighten up the clutch nut. ( 100 ft/lbs). Do not guess on something so critical!


Now she's good to go for another hard 2000 mile year!

 

[Colorado Kodiak 700]

Thanks for the great info!