technician who has received the proper training
and understands the procedures outlined in this
manual. Because of the critical nature and
precision balance incorporated into the CVT
components, it is absolutely essential that no
disassembly or repair be made without factory
authorized special tools and service procedures.
The Continuously Variable Transmission (CVT) consists of
three major assemblies: 1) The Drive Clutch; 2) The Driven
Clutch; and 3) The Drive Belt. The internal components of the
drive clutch and driven clutch control engagement (initial
vehicle movement), clutch upshift and backshift. During the
development of a Aeon ATV, the CVT system is matched first
to the engine power curve; then to average riding conditions
and the vehicle’s intended usage. Therefore, modifications or
variations of components at random are never recommended.
Proper clutch setup and careful inspection of existing
components must be the primary objective when
troubleshooting and tuning.
CVT Maintenance / Inspection
Under normal operation the CVT system will provide years of
trouble free operation. Periodic inspection and maintenance is
required to keep the system operating at peak performance.
The following list of items should be inspected and maintained
to ensure maximum performance and service life of CVT
components. See “CVT Overheating / Diagnosis” on page 3.3.
f
or more information.
1. Drive clutch rollers and bushings. Driven clutch rollers,
pins, and spring.
2. Clutch sheave faces. Clean and inspect for wear.
3. CVT system sealing. The CVT system is air cooled by fins
on the drive clutch. The fins create a low pressure area around
the drive clutch. The clutch cover, must be sealed to ensure
water and other contaminants entering the CVT area.
Drive Clutch Operation
Drive clutches primarily sense engine RPM. The major
component which controls shifting function are the shift
centrifugal weights (rollers) inside the moveable sheave.
Whenever engine RPM is increased, centrifugal force is
created, causing the rollers to push against the cam plate and
force the moveable sheave toward the drive belt. This motion
pinches the drive belt between the spinning sheaves and causes
it to rotate, which in turn rotates the driven clutch. If belt speed
is sufficient, centrifugal friction shoes on the driven clutch
overcome their return spring pressure and swing outward
against the transmission drive hub, and the vehicle (if in gear)
begins to move.
At lower RPM, the drive belt rotates low in the drive clutch
sheaves. As engine RPM increases, centrifugal force causes
the drive belt to be forced upward on drive clutch sheaves,
changing the ratio of the drive to driven clutch from low to
high.
Driven Clutch Operation
CVT driven clutches primarily sense torque, but also react to
RPM, applying and retracting the friction shoes according to
the forces applied to it from the drive belt, while at the same
time reacting to the torque at the transmission input shaft. If
the torque resistance at the transmission input shaft is greater
than the load from the drive belt, the drive belt is kept at the
outer diameter of the driven clutch sheaves (low ratio).
As engine RPM and horsepower increase, the load from the
drive belt increases, resulting in the belt rotating up toward the
outer diameter of the drive clutch sheaves and downward into
the sheaves of the driven clutch. This action, which increases
the driven clutch speed, is called upshifting.
Should the throttle setting remain the same and the vehicle is
subjected to a heavier load, the torque sensing driven clutch
will close, forcing the drive belt back up toward the outer
diameter of the driven clutch. This also forces the belt
downward into the sheaves of the drive clutch. This action,
which decreases the driven clutch speed, is called backshifting.
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