Back-Shifting; Final Gearing; 1:1 Shift Ratio; Low / High Ratio - Polaris 340 LX 2007 Service Manual

Back-Shifting

Back-shifting occurs when the track encounters an
increased load (demand for more torque). Back-shifting is
a function of a higher shift force within the driven clutch
than within the drive clutch. Several factors, including
riding style, snowmobile application, helix angles, and
vehicle gearing determine how efficient the drive system
back-shifts. The desired engine operating RPM should
never fall below 200 RPM when the drive system back-
shifts.

Final Gearing

The final drive gear ratio plays an important role in how
much vehicle load is transmitted back to the helix. A tall
gear ratio (lower numerical number) typically results in
lower initial vehicle acceleration, but a higher top-end
vehicle speed. A lower gear ratio (higher numerical
number) typically results in a higher initial vehicle
acceleration, but a lower top-end vehicle speed.
Choosing the proper gear ratio is important to overall drive
system performance. When deciding on which gear ratio
to use, the operator must factor in the decision where the
snowmobile will be ridden, what type of riding will be
encountered, and the level of performance the operator
hopes to achieve.
Gearing a snowmobile too low for extended high-speed
runs may cause damage to the drive belt and drive
system, while gearing a snowmobile too high for deep-
snow, mountain use may cause premature belt and clutch
wear.
Typically, it is recommended to gear the snowmobile with
a slightly higher ratio than the actual top speed the
snowmobile will ever achieve.

1:1 Shift Ratio

A 1:1 shift ratio occurs when the drive clutch and the driven
clutch are rotating at the same RPM.
The mathematical vehicle speed for a given gear ratio at
a 1:1 shift ratio is represented in the chaincase gearing
charts located in the Final Drive Chapter.

Low / High Ratio

Low ratio is the mechanical position when the drive belt is
all the way down into the drive clutch, and all the way out
on the driven clutch. High ratio represents when the drive
belt is all the way out on the drive clutch, and all the way
in on the driven clutch.

Driven Helix / Ramp

The helix cam is the primary torque feedback component
within the driven clutch, regardless of driven clutch type.
The beginning angle of the helix must transmit enough
torque feedback to the moveable sheave in order to pinch
the drive belt while minimizing belt slip. The flatter or lower
the helix angle, the more side force will be exerted on the
moveable sheave, while the steeper, or higher the helix
angle, the less side force will be exerted on the moveable
sheave.

PVT System Fastener Torques

Drive Clutch Bolt
(All Carbureted)
Drive Clutch Bolt
(All 2007 - Current
CFI)
Driven Clutch Bolt
Team Helix
Fasteners
P2 Cover
Team Deflection
Jam Nut
P2 Deflection
Cam
P2 SPA
Deflection
Adjuster Screw
Lock Nut
Spider
Spider Jam Nut
Drive Clutch
Cover
Starter Ring gear
9923396 - 2007-2012 EDGE/Widetrak LX Service Manual
©2011 Polaris Sales Inc.
Fastener Torque
50 Ft.Lbs.
(68 Nm)
80 Ft.Lbs.
(108 Nm)
17 Ft.Lbs.
(23 Nm)
60 - 80 In.Lbs.
(7 - 9Nm)
12 Ft.Lbs.
(16 Nm)
110 In.Lbs.
(12 Nm)
12 Ft.Lbs.
(16 Nm)
10 Ft.Lbs.
(12Nm)
280-300 Ft.Lbs.
(380-406 Nm)
290-330 Ft.Lbs.
(394-447 Nm)
100 In. Lbs.
(11 Nm)
150-180 In.Lbs.
(1-1.2 Nm)
PVT System
Note
Re-torque after
running engine.
7
DO NOT
OVER-TORQUE
Apply Loctite 243
OR Loctite 242
with Primer N
Apply Loctite 271
Use cross pattern
7.3