[Jamm]

I am not sure were to put this topic, but this reagards all CVTech Trailbloc primary clutches.

The CVTech Trailbloc is a new animal for me. I am used to snowmobile clutching, and have some basic knowledge about CV clutches, and how to tune.

With this new Cforce 850 I am not happy with the stock clutch tuning, main issue is the primary engagement. With snowmobiles I used to shim the spider, and to shim the belt to moving sheave clearance. Spring, weights, secondary helix, secondary spring(s) have been used to adjust engagement rpm, and to suit the power/torque profile. Have clutched my 400 hp turbo sled to be able to move slow as a turtle, and to reach reasonable top speed.

I know there is a lot of different CVTech primary springs and weights, how about primary shims, rubber block profiles, secondary helixes, and springs?

[NMKawierider]

I am not sure were to put this topic, but this reagards all CVTech Trailbloc primary clutches.

The CVTech Trailbloc is a new animal for me. I am used to snowmobile clutching, and have some basic knowledge about CV clutches, and how to tune.

With this new Cforce 850 I am not happy with the stock clutch tuning, main issue is the primary engagement. With snowmobiles I used to shim the spider, and to shim the belt to moving sheave clearance. Spring, weights, secondary helix, secondary spring(s) have been used to adjust engagement rpm, and to suit the power/torque profile. Have clutched my 400 hp turbo sled to be able to move slow as a turtle, and to reach reasonable top speed.

I know there is a lot of different CVTech primary springs and weights, how about primary shims, rubber block profiles, secondary helixes, and springs?

This could easily become a long discussion however lets start with the basics on these and work up from there. These CVT systems function the same as most other CVT systems in that between the settings of both, the load and torque is sensed and shifting is done to that end. As is most CVT system tuning, the load is always set first by adding...or removing resistance in the secondary or driven clutch. This is done with different springs in most however not with the CVtech which uses the torsional abilities of the spring and a slight bit of the compression to achieve this. They achieve this with anchoring each end of the spring and twisting the helix to set it the ramps on the hard plastic pads. Multiple pin holes on either end make for many different "preload" settings. We call this "Clocking" as one thinks of the degree of preload from zero on a degree wheel such as this:



Although the pads are replaceable to my knowledge there is no other helix with different ramp angles.

Moving on to the primary or Drive clutch, engine torque, power delivery and engagement is adjusted by way of flyweights and the spring. There are no shims to adjust. Lower RPM engagement of the belt can be achieved by using either heavier fly weights or a spring with a lighter 60mm pressure rating. The same is true in reverse for higher engagement needs. Adjusting for higher or lower overall RPM or power range is also a matter of the spring and flyweight combination so both must be taken into account when you decide. Here is a primary spring chart.

     

[Jamm]

This could easily become a long discussion however lets start with the basics on these and work up from there...............

Thanks....

[glutengimp]

You guys seem really knowledgeable. I joined the forum because of the same issue...

What would you recommend me doing with the CVT if I want it almost as "spongy" as possible in the start?

[NMKawierider]

You guys seem really knowledgeable. I joined the forum because of the same issue...

What would you recommend me doing with the CVT if I want it almost as "spongy" as possible in the start?

I think you emailed me and I answered by changing the weights and spring.