SECTION 06 - DRIVE SYSTEM
MMC2005-001_06A.FM
06-59
1. Slide lower O-ring of deflection scale to speci-
fied measure.
2. Slide upper O-ring to 0 (zero) on the force scale.
3. Apply pressure until lower O-ring is flush with
edge of rule and read force on the upper scale
at top edge of O-ring.
1. Upper O-ring — force
2. Force
3. Lower O-ring — deflection
4. Reference rule
5. Deflection
CHAINCASE GEARING
Contrary to popular belief, small gear changes do
not directly affect top speed as long as the clutch-
es are functioning properly. Gearing one or two
teeth taller on the top will not generally make the
vehicle any faster on top end unless the clutches
are fully shifted out and the engine is starting to
overrev.
With the TRA clutch, we have about 20 percent
more shift ratio available compared to other de-
signs. Because of this, we have been able to lower
the gearing in our chaincase considerably. Yet, we
still have the same overall top gear ratio because
of the 0.8:1 top ratio of the TRA clutch.
This gives us better belt life by allowing our clutch-
es to
slip
for a shorter period of time at engage-
ment. It also provides more torque to the drive
axle for acceleration.
Most snowmobiles are geared on the
high
side
from the factory. They are usually geared for 8 -16
km/h (5-10 MPH) more than they would reach in
average conditions. Because of this, the belt does
not seem to go all the way to the top of the drive
clutch. This is a normal situation. Snowmobiles
run under widely varying conditions. If all snow-
mobiles were geared to attain a full shift under av-
erage conditions and then the vehicle were run on
a perfectly smooth frozen surface, it would easily
shift out to its geared top speed. Since the drag is
so low under these conditions, the engine would
begin to over-rev, eventually lose power, possibly
damage the engine, and you will not achieve top
speed.
There are other factors involved here also. As
clutches shift through their range, the efficiency
with which they transmit power decreases as the
clutch ratio exceeds about 1.5:1. Efficiency also
drops as belt speed (RPM) increases. For opti-
mum chaincase performance ensure that you use
the synthetic chaincase oil.
Because newer clutch designs shift beyond a 1:1
ratio, belt speed increases dramatically and the di-
ameter that the belt follows around the driven pul-
ley decreases considerably. This wastes energy
and efficiency as the belt is being bent around a
smaller diameter and centrifugal force is trying to
pull the belt into a circular path instead of following
the pulleys.
This is why for years manufacturers kept their
clutch ratios around 1:1 to keep belt speeds down.
Now with the advent of larger displacement, high
torque, lower RPM engines, we can use overdrive
transmissions and still keep our belt speeds within
reason.
As we mentioned, as belt speeds go up, efficiency
drops. This is one reason many radar runners gear
extremely high sometimes even approaching 1:1
in the chaincase. They have found through diligent
testing that they can achieve a higher top speed
without shifting their clutches all the way out be-
cause of a decrease in belt speed which means an
increase in transmission efficiency. That is their
bottom line.
A00D08A
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Содержание ski-doo MACH Z 1000 SDI
Страница 1: ...Mmc 2005 001 Racing FH8 Wed Sep 15 15 27 01 2004 Page 1 C M Y CM MY CY CMY K...
Страница 118: ...04 36 MMC2005 001_04A FM SECTION 04 SUSPENSION SC 3 SC 4 RAS SC IV REAR SUSPENSION 0...
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Страница 196: ...05 72 MMC2005 001_05A FM SECTION 05 ENGINE PREPARATION FUEL TANK AND FUEL PUMP All Models except SDI 2 4 3 1 A33C2VS...
Страница 289: ...SECTION 06 DRIVE SYSTEM MMC2005 001_06A FM 06 27 422 A01D3JA 417 222 562 427 A01D3KA 417 222 677...
Страница 473: ...SECTION 12 SERVICE TOOLS MMC2005 001_12A FM 12 29 N Scratch remover P N 861 774 800 APPLICATION All models...
Страница 476: ...MMC2005 001_13A FM 13 1 SECTION 13 ACCESSORIES TABLE OF CONTENTS 0 ACCESSORIES 13 02...
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