The job of the transmission is to change the speed ratio
between the engine and the wheels. The transmission uses a range of gears --
from low to high -- to make more effective use of the engine's torque as
driving conditions change. The gears can be engaged manually or
automatically. Today's side x side vehicles all use a type of automatic
transmission called a continuously variable transmission or CVT.
Unlike traditional automatic transmissions used in cars that
are much too heavy for a side x side vehicle, CVTs don't have any sort of
gears. The CVT operates on a pulley system
that allows an infinite variability between highest and lowest gears with no
discrete steps or shifts.
CVTs used in Rhinos, RZRs, Rangers,
Teryx and Prowlers have three
basic components:
- A rubber v-belt
- A variable-input "driving" pulley
- An output "driven" pulley
The variable-diameter pulleys are the key to a CVT. Each
pulley is made of two cones facing each other. A belt rides in the groove
between the two cones. When the two cones of the pulley are far apart, the
belt rides lower in the groove, and the radius of the belt loop going around
the pulley gets smaller. When the cones are close together, the belt rides
higher in the groove, and the radius of the belt loop going around the
pulley gets larger.
One of the two pulleys is connected to the crankshaft of the
engine. This pulley is typically called the drive pulley. The second pulley
is called the driven or output pulley because the first pulley is turning
it. The driven pulley transfers energy to the transfer case and onto the
differentials, through the axles and out to the wheels.
Excess heat is a real killer of CVT belts. Excess heat is
created by belt slippage. The belt is cooled by air flow, so anything you do
to slow the flow of air over your belt will make your belt even more hot.
CVT belts slip as a normal part of operation, but limiting
the amount of slip is key. Adding extra weight to the vehicle without
changing how the clutch operates will cause more slipping. So will over size
tires and added performance (pipe, air filter and other performance work).
Added stress on the engine while driving in mud or in the sand dunes will
also create belt slip.
While it is impossible to set up a clutch on a UTV to handle
all variations or vehicle weight, horsepower and driving conditions, it is
possible to adjust your clutch with different springs and weights for the
majority of conditions. Think of it as tuning your CVT to your vehicle
modifications and riding areas.
Since the RZR's engine sits sideways, the belt is in between
the seats and right behind them.
Remove seats and center cover behind the seats to expose the CVT
Remove cover to expose primary and secondary clutch and CVT belt
Slide secondary clutch off then use clutch puller to remove primary clutch.
Both primary and secondary pulleys removed.
Primary - We will be replacing the spring and the weights here.
Cover removed so spring can be replaced. This is a balanced unit so mark it
so you can get it back together the same way.
Old vs. New Spring
New clutch weight
Secondary - We will be replacing just the spring here.
After you get it back together, make sure that you torque to specifications.
Testing - Low RPM on left. High RPM on right.
Aftermarket clutch kit from EPI - We went with kit #WE436342 (25" - 26"
Tires, Dual Exhaust and fuel controller)
EPI carries a complete line of clutch kits to work with your machine and
your riding style... everything from trail riding and heavy duty
hauling/working to mud running with oversized tires.
- Kits are designed to improve the performance on or off the trails without losing
the reliability of your ATV/UTV.
- Kits are more efficient in transferring the power of your ATV/UTV down to the
tires.
- Kits are also designed to improve low and mid-range acceleration.
- Helps to decrease belt slippage, which will decrease clutch heat.
- Each kit will enhance back shifting and throttle response.
- Each clutch kit has been field tested to assure your satisfaction.
- Kit designed for stock motor and stock exhaust.
- Kit components vary by model and style of kit.
EPI (Erlandson Performance Inc.) -
www.erlandsonperformance.com
