If going a a long trip just strap a gas can on the rack.

 

Ok rooster you make it shound like the Pvt is one single geared, and the more rpms the faster you go, IT SIMPLY HAS GEARS.


And Deej, what are you talknig about the clutch sizes changing? There is onyl 1 clutch, and the cluthces dont change its the gears!


CHRIS

 

I will use whatever amount of gas it takes to have fun!!!!!!!!!!! If it takes 5 gallons a day so be it.

------------------
99 Sportsman500,2000 Trailboss 325,69 Mustang 428scj

 

clindst,

There are indeed 2 clutches. They are referred to as the "drive clutch" (the clutch on the motor), and the "driven clutch" (the clutch at the gearbox on an ATV - or at the jack shaft on a snowmobile).

When the machine is idling, the drive clutch (at the motor) is opened up wide leaving the belt, effectively, on a small pully. The driven clutch (at gearbox) is closed up leaving the belt, effectively, on a large pully. This setup (small pully in front, large in back) provides a low gear ratio for take-off. Think of a bicycle gearing.

As you speed up, the drive clutch closes up and the belt rides higher and higher in the front. The driven clutch opens up and the belt rides lower and lower in the back. This setup (large pully in front, small in rear) provides a high gear ratio.

As you drive, the sizes of these two clutches are constantly changing with engine speed, ground speed and torque. This gives you a continuously variable gear ratio that changes automatically. If designed and setup correctly it will always be in the right gear.

The gearbox on a Polaris machine is an incredibly simple device. It does not provide any gear ratio shifting at all - simply shifting for high/low and reverse. Its purpose in life is simply to provide a method to reverse the drive line, shift to low, and a place to attach the rear drive axles - a cross between a transfer case, a gearbox, and a differential.

In a snowmobile (that doesn't have reverse), the 2 clutches and belt drive the track directly (via a jack shaft and a chain). Snowmobiles with reverse can be likened to the ATV in that they have a gearbox, but it simply provides a method of reversing the driveline (and shifting to low on some machines).

The two clutches do all the shifting, the gearbox does no in-motion shifting.

This clutch/belt system is very reliable and has been used in snowmobiles since the dawn of time.

I will try to find a web reference showing the workings of the system. I'll get back to you on this one.

The drive clutch (on the motor) is the primary clutch. It does most of the work, the driven clutch simply follows its lead.
The clutch kits (roller clutch etc) concentrate on modifying the primary clutch, but also play with the secondary clutch. They don't result in any more horsepower, they simply make the stock clutch do its job better. The opening and closing of the 2 clutches can be changed by changing springs (in both clutches) and weights (in the drive clutch). Changing these items can result in a change of initial engagement speed, and also the torque sensitive "shift" pattern. As the primary clutch closes with engine speed, the outer clutch face rides inward on nylon buttons. The roller clutch replaces the button setup with bearings - much less friction. Fellow posters like Bill C, and others, have installed clutch kits and report smoother initial engagement and better throttle response.

Sorry for the book but ... you asked!

DJ

 

Deej, that was one of the most thorough and straight forward explanations of the polaris variable transmissions I have seen to date.
Thanks
Joe

 

The CVT sounds very similar to the design on my first "motorized" bike, a Rupp mini-bike (years ago). Of course, it wasn't called a transmission, just a torque converter, but it got the job done.


-Mike

 

joemag500,

Thanks for the kudos. We participate in the forum to share info. I appreciate the info I get and am happy to share info I have.

I should correct something I said earlier. I indicated that a clutch kit does not create extra horsepower. This is true, the engine output does not change as a result of clutch mods, but, there can be a change in horsepower at the wheels. A clutch kit can help get the engine horsepower to the wheels more efficiently. The clutch kit can affect initial engagement speed, low end torque, high end torque, shift pattern, top speed, and more.

DJ

 

deej,
sorry i was getting it confuzed with a manual shift like a car or dirt biek, with a drive gear adn another set of gears that change not clutches sorry for the nessecity of the book

hehe