primary/ secondary clutch tuning

On the drive clutch, you want to swing as much weight as you can and still maintain operating rpm, your drive clutch spring initial force determines clutch engagment rpm, the finish rate holds the shift back. So effectivaly there a too ways you can increase operating rpm, less fly weight or greater final rate on the spring.

Driven clutch is your shift control, so to answer your question, does greater pressure hold back the shift? I say yes. It also increases the back shift. Also the steeper the angle of the helix the faster the upshift/the slower the back shift. a shallower helix angle will upshift slower/backshift faster.


I am by no means a cultching expert, but this is my understanding.

Start with a viewable tach.

Dissasemble the primary and find it's condition and part #'s list, compare it to a Polaris RMK700 parts fische, low miles or not if it was not maintained/cleaned regularly it could have worn bushings and such.

As a Twoski rider I watched most of my friends expect their machines, mostly Polaris, to be turn key, four or five years later they were searching for replacement P85's at the swap meet, they were allways amazed like new tires on their bike.

Get your machine to mimic the one it's engine came from and you will know where to start. After a few of us trying to get some of the local experts to work with us some would'nt take the time, others just offered a baseline solution comparable to a similar powered Twoski, without understanding or riding our machines. We have to figure it out on our own, especially when doing a project such as yours.

Eighth inch sounds right on the belt, Polaris owners manual will list max rpm,you altered that, get a tack, watch for that number, and don't let it go too much over it. In stock Rotax form, by copying the 500/600/800Summits OEM clutching specs part for part, and jetting as best I can, ATTAC's too. Now most are gravitating towards the Artic Cat roller secondary, for our regular altitude window in our Western riding conditions it just keeps getting better with no end in sight.

So many variables, at least you are starting with a mountain specific powerplant, a legendary one at that. Except for a few of you experts out there we're all stacking fixes on an easy sollution. Motor, clutching, suspension, and track intended for your conditions and you've got the right starting setup, fine tune from there.

On a flat run , do you know where your highest rpm hit is ?