Yamaha Rhino
CVT Belt Guide
Constant Variable Transmission or CVT
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.
CVT Air Filter?
Lots of people have been sold on the need to put a
CVT air filter on their Rhino to
prevent debris from entering the belt area. While it isn't a great idea to
get sand in your CVT, a dirty CVT filter may cause even more damage.
While the filter does help keep the belt area cleaner, there
is debate on whether a dirty CVT Filter causes more heat in the CVT area
leading to belt failure. While running a high speeds for extended periods of
time, a lot of heat is generated. the area is cooled by fresh air.
If you have a CVT filter that is clogged up, you are hampering the cooling
of your belt and this can cause a belt failure.
Most people suggest not using air filter oil on your CVT
breather as it will more quickly clog your air filter and slow down the flow
of cool air into your CVT.
CVT Belt Failure
While on our Mexico
UTV Run in May 2008, our group experienced four CVT belt failures. Every
Rhino that had a belt failure was running with a CDI and a CVT air filter.
There are a few theories to why the belts failed. Some thought the
aftermarket CVT filters are not letting enough cool air in. Others
thought the CDI which allows higher speeds was the cause.
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.
A spare CVT belt is a good thing to keep with your Rhino at
all times.
How to change a Rhino CVT Belt
Remove seat base and plastic in front of seat. Remove bolt
from inner/front seat base that goes around below shifter.
Remove the bolt holding hose clamp for the coolant line.
Push hose down and out of the way so you can remove the clutch case housing
through framed opening.
Remove cover. Bolt
lengths vary so make sure you mark them.
Cover removed - Sheave is on the right.
Remove sheave "guard"
Guard removed
In order to remove tension from the V-Belt, it is necessary
to install two bolts into the secondary fixed sheave.
Links:
Replacement Rhino CVT Belts
- OEM Yamaha CVT Belt: 3B4-17641-00-00
- EPI Super Duty CVT Belt:
WE262233
- Neoprene compounding.
- Designed for higher horsepower UTV's.
- The highest quality belt available.
- Deep Double Cog style belt helps reduce clutch heat.
- Higher quality control & closer tolerances used in manufacturing.
- Designed for Severe Duty applications such as high horsepower, heavy load
& aggressive riding styles.
Clutch Kits
After you have made a few changes to your Rhino, it may be a good time to
think about a clutch kit. CVT belts slip as a normal part of operation, but
limiting the amount of slip is key to longer belt life and performance. 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 that apply for you.
A typical clutch kit will come with a secondary spring and weights.
Changing the springs for the secondary sliding sheave
will help manipulate progression rate and engagement RPM.
If you want to play around with creating your own "kit" there are a few
things to keep in mind. In general, there are a few different spring
choices:
Blue Spring is slightly stiffer than stock spring
Orange Spring is stiffer than blue spring
White Spring is stiffer than
orange Spring
Clutch weights are available in 14 gram, 16 gram, or 18 gram
weights. Different clutch weights have a direct affect on both progression
rate and engagement RPM.
Other kits may also include a new severe duty belt and sprague springs.
Rhino Clutch kit with severe duty CVT belt - EPI
Yamaha Rhino Clutch Kits - EPI
Yamaha Rhino Clutch Kit (Duner's Kit) from
KMS Performance
Yamaha Rhino
Clutch Kits - Alba Action
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