BOMBARDIER ski-doo Nordic 640ER 1973 User manual

II 957 and 958, tests began on
what is considered the forerunner of the
Ski-Doo" We experimented With many
different frames and engines-in search
of a machine for one or two pas-
sengers By the fall of '58, the first pro-
was Initial tests made It
ObVICiUS the machine could hold Its own
In the recreation market Production be-
gan one year later and 225 machines
were sold at about $1 ,000 each
Like s predecessors the '73 Ski-Doo
snowmobile is a combination of
ness, economy, strength and
And yet, with ail this. it has one
other additional feature
Each model In each series has a com-
plexity of characteristics that distin-
quishes itself as part of a bold breed
... the Ski-Doo snowmobiles.
At Bombardier. we fully realize that the
purchase of a snowmobile IS a very im-
portant decision For this reason, we
have ensured that each Ski-Doo snow-
mobile IS backed up an International
Ski-Doo Distributor Dealer Network
whose factory trained personnel are
to give you
prompt and ef-
service wherever you are in Snow
Country
Furthermore, each dealer is prepared to
serve you With .nforrnation. parts and
accessories Feel free to contact him
At this time we wouid like to thank you
for your patronage and weicome you to
vvinter EnJOy but remember
Safety depends on you, the driver, the
condition of your vehicle and nature of
the terrain
Aii of the information, illustrations and
component /system descriotions con-
tained In this manual are correct at the
time of However, Bomb
ardier limited reserves the right to
make changes in design and spscifica-
nons. and / or to make additions to or
Improvements in rts products Without
irnnnc:rnn any upon itself to
install on its products previously
manufactured
This manual has been published by the
Technical Information Centre, Bomb-
ardier Limited, 8600 Decane Bivd,
Montreal 307, Quebec, Canada

Skandic
Carry-Boose
Bombardier
*The following are trade marks of Bomb-
ardier Limited.
Ski-Doo Valmont
Ski-Boose T'NT
Nordic Elan
Alpine Blizzard
PATENTS and DESIGNS
This vehicle IS covered by one or more of the fol-
lowing patents and desiqn regIstratIons
Canadian Patents 605.317 710.592-
724.395 - 853.505
United States Patents 2.899.242 -3.066.546 -
3.536.153
Canadian Designs 01I 217 F 128172 -D! 1249
F/31317 and '316 -032.479 - 032.535-
032.655 to '657 032.661 to ·669
33.982 -33.933 - 34.006 and 007
United States Daslgn Patents
Des 221.332 to 334 -
Des
221.637and·638-
Des 222.244 to 24 7
Others Swedish Design No.
6038
SWISS Desiqn No. 104.756-
Norwegian Design No 51.444
WHAT YOU SHOULD KNOW
BEFORE FIRST RIDL 2
SERVICE AREAS 3
00·5 4
DONT·S 5
GOOD DRIVING TECHNIQUE 6,7
CONTROLS/ INSTRUMENTS 8,9
FUEL MIXING 10.11
BREAK-IN PERIOD
PRE-START CHECK
12
IN CASE OF EMERGENCY 13
STARTING PROCEDURE 14
lUBRICATION 15, 16,17
MAINTENANCE 18, 19,20,21,22
EMERGENCY GUIDE 23
TROUBLE SHOOTING 24. 25
OFF SEASON
STORAGE
26.27.28,29
PRE SEASON PREPARATION 30
SPECIFICATIONS 31
WARRANTY 32
AI! rights reserved ((:,Bombnrd!'?-! Limited 1972

2
To many of us, Winter is a revealing ex-
perience. Weather, atmospheric condi-
tions, snow surfaces, individual driving
habits and vehicle have consider-
able affects We ask you familiarize
yourself
with them ... read the owner's
manual; it has been prepared to ac-
quaint you with the operation of your ve-
hicle, its safety aspects and systems as
well as preventative maintenance
procedures that must be periodically
upheld
... all aimed toward a more en-
jovable Winter season.
Observe the fo!lowing precautions:
@ Throttle mechanisrn should be
checked for free movement
before
starting engine.
eEngine should be running only whsn
pulley guard is secured in place
@ Navel' run engine without drive belt
installed an unloaded engine
can prove to be dangerous.
l1li Never run the engine at high R.P.M.
when the track of the vehicle is raised
off the ground.
~ It can be dangerous to run
with the
cab open.
eProlonged sitting while riding over
rough terrain may cause kidney and/or
spinal discomfort, specially for the driver
or passenger having an existing back
weakness.
eGasoline is flammable and explosive
under certain conditions. Always per-
form procedures in a well ventilated
area. Do not smoke or allow open
flames or sparks in the vicinity. If gaso-
line fumes are noticed while driving, the
cause should be determined and cor-
rected
without delay.
e Under no circumstances should you
wear loose clothing or scarves that
could become entangled with moving
parts of your snowmobile.
@Your snowmobile is not designed to
be operated on public streets, roads or
highways. In most States and
Provinces,
it is considered an illegal operation.
e Hidden telephone guy wires or road-
side ditches can cause serious accidents.
@Your snowmobile is not designed to
be driven or operated on black top, bare
earth, or other abrasive surfaces. Abnor-
mal and excessive wear of critical parts
is inevitable.
G Always wear an approved snow-
mobile safety helmet. Be informed on
local laws legislating the sport.
@Maintain your vehicle in top mechani-
cal condition at all times.
Please read and ul'uterstsnd all other
warnings contained elsewhere in
this manual.

CANADIAN DISTRIBUTORS
AMERICAN DISTRIBUTORS
CRAiGTAYLOR EQUIPMENT CO Alaska
P.O Box
3338, Anchorage,
Alaska 99501
Name of Distributors
ALPINE DISTRIBUTORS
3206 - 28th Ave, Vernon, B.C
ATLANTICSKI-DOO LTD
PO Box
670, Sheciac. N.B
BOMBARDIER ONTARIO LTD
28 CUrriesr.Barrie,
o-».
BOMBARDIER QUE LTD
1350 Nobel St Boucherviile Que
BROOKS EQUIPMENT LTD
Box
985, Winnipeg 21, Man
HUDSON'S BAY CO
121 Richmond W
Toronto,
ant.
JWRANDALL LTD
PO Box
757, Corner Brook,
Newfoundland
TRACTEQUIPMENT LTD
14325 - 114th Ave,
Edmonton, Alta
Coverage Area
Bntlsh Columbia
Prince Edward Island
Magdalen Island
Nova Scotia
New Brunswick
Ontario
Quebec
Manitoba
Saskatchewan
North-West
Territories
Newfoundland
Yukon
Alberta
Name of Distributors
BOMBARDIER EASTINC.
Raliroad St.. Lee,
Massachusetts
01238
BOMBARDIER WEST INC.
609 West Broadway.
Idaho Falls, Idaho
83401
ELLIOTT& HUTCHINS INC
East Main Street Road,
Malone. New York 12953
Coverage Area
Massachusetts
Connecticut
Rhode Island
California New Mexico
Nevada Arizona
Montana Kansas
Idaho Nebraska
Wyoming Washington
Utah Oregon
Colorado
New York
Pennsylvania
New Jersey
Maryland
Delaware
District of Columbia
Virginia
HALVORSON INCORPORATED
325 South LakeAvenue,
Duluth 2, Minn
55802
HEATH INTERNATIONAL INC.
33737 - 32 Mile Road,
Richmond, Mich. 48062
TIMBERLAND MACHINES INC
10 Main St North, Lancaster,
New Hampshire
03584
North Dakota
South Dakota
Minnesota
Wisconsin
Iowa
lIi,nols
MIssouri
Upper Michigan
Lower Michigan
Indiana
OhiO
Tennessee
Kentucky
WVirginia
Maine
New Hampshire
Vermont
3

4
•Register your Ski-Doo snowmobile at
your nearest Licensing Bureau, where
State or Provincial Laws require It. and
affix Registration Plate to the vehicle
Carry your registration certificate with
you It provides proof of ownership In
the event that the vehicle becomes lost
or stolen.
•Obtain your State or Provincial book-
let on snowmobiling It gives valuable
information on the neighbouring snow-
mobile trails and the laws governing
snowmobiling in your particular area.
• Observe all posted snowmobile signs
Not all private landowners allow snow-
mobiling on their property. You can
have just as
much fun, even more so, by
traveling elsewhere.
• When With others, limit your actions
to the experience of the main body.
Show the Inexperienced driver how
to
properly handle a snowmobile.
• Always travel with at least one other
snowmobile, especially in unfamiliar ter-
ram or on trail rides Even In snow-
mobiling, a pair beats one of a kind.
•If you are planning to explore new
areas, leave word of your approximate
whereabouts and estimated time of re-
turn with someone.
• Always make a full stop then look
carefully in both directions before cross-
Ing roads When traveling in pairs or in a
group, have one member direct the oth-
ers across singly
• Use a rigid hitch or tow-bar when pull-
mg any sled or trailer behind your Ski-
Doo snowmobile. Rigid hitches
prevent
tailgate collision when going downhillor
on sudden stops
• Be extremely careful when giVing chil-
dren a
ride Go more slowly andcheck
frequently. Small children, are
far safer
in a Ski-Boose' sled than on the seatof
your snowmobile
•When trailering your Ski-Doo snow-
mobile, secure it solidly at both ends
protect it with abright cover (Ski-Doa:
cover) then check that trailer hitch and
safety chain are secure and that brake,
flashers, position and parking
lights are
all in working order.
"Trademark Bombardier Limited

• Don't cut across in front of the line of
travel of another
snowmobile Don't tail-
gate, collision, or the threat of it, is
serious
with any moving vehicle
18 Don't risk injury or damage to your
machine with needless and foolish
stunting Don't .. Jump" your snow-
mobile This part of snowmobiling
should be left to the professional
"stunt" men.
18 Never ride on railway tracks. The
sound of your moving vehicle drown
out noise of approaching trains Your
vehicle may also
become caught in
track junctions. In many States and
Provinces snowmobiling on railway
tracks constitutes an infraction of the
law
/I Never cut through fences or attempt
to run over them.
18 Don't cross a river or lake without first
being positive that the thickness of the
Ice is sufficient to support
both you and
your vehicle Your life may depend on
it, If at all in
doubt. take an alternate
route.
18 Unless you are certain of a fueling
stop, never travel
further than Vz of the
fuel remaining in your
tank Even then.
leave yourself asafety margin. Remem-
ber
that asnowmobile does not neces-
sarily travel the same distance each
time on the same
amount of fuel Alot
depends on speed,
snow conditions of
the trail and adjustment of the
carburetor
18 Don't drive vour snowmobile In the vi-
cinity of skiers and keep off Ski trails Al-
ways respect the rights of those who
eruov winter In another way
18 "If you drink don't snowmobile! If
you snowmobile, don't drink!" Re-
member alcohol and gasoline don't mix.
18 Don't lend your snowmobile to
inexperienced or under-age drivers. In
many cases it is the vehicle owner and
not the rider
that is responsible for
mishaps. Check
State or Provincial min-
imum age limits for drivers.
18 Don't leave your keys In the ignition
switch It presents an invitation to
thieves and a
danger to children.
18 Don't get hands or feet In track or
moving parts. If your vehicle gets' 'bog-
ged" down, stand to one side, squeeze
the
throttle lightly, lift the rear grab
handle, and walk out
the machine.
5

Everyone knows, or should know, the
difference between a good snowmobiler
and a poor one
Most beginners think
that snowmobiling
IS amatter of
starting the engine riding away.
It's
not so. There are right and wrong ways
to go about it. Here are some of the pre-
ferred methods
Tips
Where possible, enter asnowmobile
training program Thoroughly know your
vehicle and how to drive it before at-
tempting difficult or rapid manoeuvers.
Driving Positions.
There are three driving POSitions on a
snowmobile-Standing, Kneeling or Sit-
Each presents certain advantages
depending on the nature of the terrain,
snow conditions, the turns you desire or
the personal of the driver
Standing-This position is undoubtedly
the best for climbing steep hills, trav-
eling a short stretch of bumpy trail or
when manoeuvering in deep snow. In
this position. however, always keep your
knees slightly flexed to absorb surface
shocks
Knseling-crossing a steep slope, for
example, from side to side, you will find
the kneeling position adefinite advan-
tage. Place one foot on the footboard
(on the high side of the hill), the oppo-
site knee on the seat then lean into the
hill.
Warning: Side !'Iills and steep slopes are
not rEl1::ommended for a beginner.
An alternate recommended kneeling po-
sition and one that is frequently used,is
to place both knees on the seat, with
one foot on each side, ioosely pressing
against the seat.

Sitting-for all normal driving Feet
should be on the footboards, body mid-
way back on the seat Avoid placing
your foot Inside the support braces of
the footboard
Warning: Prolonged sitting while riding
over rough terrain may cause kidney
and/or spinal discomfort, specially for the
driver or passenger having an eXisting
back weakness.
Turning.
To snowmobile properly you must learn
to
"body english", (using the weight or
position of your body). Shifting to left or
right as the turn demands and keeping
your center of gravity as
low as possible
will give you the mark of an experienced
snowmobiler.
Moving your body
weight toward the
front of the vehicle, particularly In hard-
packed snow, adds pressure to the skis
and
Ski runners so that they bite more
deeply into the snow surface
Icy Surface.
Ice or extremely hard-packed snow can
be difficult to negotiate as both skis and
track do not have much traction. Best
advice is to slow
down and avoid rapid
acceleration or braking.
Deep Snow.
Use the standing position recom-
mended earlier and if your vehicle con-
tinues to make reasonable headway, re-
sponding to light changes in
acceleration, you are safe enough to ex-
plore new areas. If not, turn in as wide
an arc as possible and look for firmer
trails.
7

8
Steering
Rotation of the handlebar causes a
push-pull
action on the steering linkage
and forces the skis to turn in the re-
quired
direction
Throttle lever (A)
When depressed, the lever controls the
engine speed and the engagement of
the transmission. When lever is re-
leased
the engine speed returns auto-
matically to Idle
Brake lever (B)
When lever IS depressed, the brake IS
applied. When released, it automatically
returns to rts original position Braking
effect
IS proportionate to the applied
pressure on the lever
Ignition Switch (C)
Key operated, 3 position switch
(OFF/ON/START) To start engine, turn
key fully clockwise to START position
and hold. Return key to ON position im-
mediately engine has started.
Headtamp Dimmer Switch (D)
The dimmer switch allows correct selec-
tion of headlamp beam To obtain Hi or
Low beam simply depress switch A HI
beam
indicator IS mounted in the ta-
chometer dial.
Note; The angle of your headlamp
beam has been pre-adjusted prior to de-
livery Should you wish readjustment,
turn upper or lower adjusting screws to
obtain desired beam position.
Kill Button (E)
For emergency stops, press button
down Into lower position. Before re-
starting engine always depress
button
into released upper position.
The driver of this vehicle should familiar-
rze himself with the function of this de-
vice by using it several times on first
outing, thereby being mentally prepared
for
emergency situations requiring its
use
After such a situation, the source of
malfunction should be determined and
corrected before re-startmq engine
Manual Starter (f)
Auto-rewind type located at lower right
side of console. To start engine pull
handle. (See Starting Procedure)

Gear Shift lever (6)
Three position lever, (FORWARD/
PARK/ REVERSE). Push up for forward,
center for park and down for reverse.
W~ming: Do not re-posltion gear
shift lever while snowmobile is in
motion.
Choke (H)
Pull button to engage choke, push to
disengage. The choke should always be
used
for easier cold engine starts. After
engine IS warmed up however, it is not
necessary to use choke when starting.
lighter (I)
Push in to activate, lighter pops up auto-
matically when lit.
Headlamp Retract lever (J)
Two position (PUSH/ PULL) lever To ex-
pose headlamp, pull lever Push to
retract
light Switch (K)
With engine running, engage switch to
illuminate both headlamp and tail!Jght
Tachometer (l)
Direct-reading dial indicates (in thou-
sands), the
number of revolutions per
minute
(RPM), of the engme .
Fuel Gauge (M)
Direct-reading dial Indicates the amount
of fuel in the tank.
Speedometer (1\1)
Direct-reading dial indicates the speed
of the vehicle in miles per hour (M
PH)
6-digit odometer records the number of
miles
travelled
Upper Access Door lock (0)
To gam access to spark plugs, turn door
lock then lift
door and remove
lower Access Door
lift lower access door to gain access .to
carburetor.
Caution: Serious engine damage may
occur if your vehicle IS operated With
the carburetor air intake tube removed.
Rear Compartment
Recessed underseat compartment.
Ideal location for spark plugs, belt rope,
etc. Pressure lock fastened. To adjust.
simply tighten or slacken adjusting nut.
Tips
Emergency materials should be
wrapped
In foam or similar material.
This will prevent possible damage to
breakable items
when traveling over
rough or bumpy terrain.
9

10
With Ski-Doo snowmobiles, the oil must
be added to the gasoline in pre-mea-
sured
amounts then both oil and gaso-
line should be
thoroughly mixed to-
gether
before fueling the tank
Which Gasoline to Use
The correct gasoline is Regular qaso-
line. (not less than
88 octane), available
from all service stations
Caution: Never experiment with other
than recommended fuels or fuel ratios
Never use no lead
gasol:net, naphta.
methanol or similar
products
recommend
Which Oil to Use
Use concentrated Ski-Doo' oil avail-
able from your Ski-Doc dealer This type
of oil has specially
formulated 011 bases
to
meet the lubrication requirements of
the Bombardier-Rotax engine
Caution: The carburetors of the 19 73
Ski-Doo snowmobile have been cali-
brated for a mixture of gasoline and
concentrated Ski-Doo oil Unless ab-
solutely necessary, do not use regular
snowmobile oil If such oil is used, ob-
serve mixing instructions on the
con-
tamer. Never use outboard or straight
mineral oils
fuel Mixing Ratio
The Importance of USing thecorrect fuel
mixture
cannot be overstressed Prior
experience has shown that en Incorrect
fuel ratio results
in seriousengine dam-
age. The correct fuel/oil ratio IS 40/ 1
5 gallol1s, gasoline plus
1 pint concentrated Ski-DOG
oil :::::: correct fuel mixture,
Note: To facilitate fuel mixing, oil
should be at room temperature.

fuel Mixing Procedure
To mix the gasoline and oil always use a
separate clean container. Never mix
directly in your snowmobile tank. For
best results, acquire two containers, er-
ther plastic or metal. Draw from one un-
til empty then use the second one.
Warning: Gasoline is flammable and
explosive I.lnder certain conditions.
Always perform procedures in a wen
ventilated area. Do not smoke 01' al-
low open flames or sparks in the vi-
cinity. If gasoline fumes are noticed
while driving, the cause should be
determined and corrected without
delay. Never add fuel while engine is
running.
\$ Pour the full amount of Ski-Doo oil re-
quired for the total mixture into the
container.
@Add approximately half the amount of
gasoline to be mixed.
c> Shake the container thoroughly.
e Add the remainder of the gasoline.
e Once again thoroughly agitate the
container.
e Usina a funnel with a fine mesh
screento prevent the entry of water and
foreign particles, transfer mixture from
container into the snowmobile tank.
Note: When USing pre-mixed fuel. al-
ways shake the container thoroughly as
the oil has a tendency to settle.
Warning: Never 'top up' gas tank before
p~acil'lg vehicle in a warm area. At certain
temperatures. gasoline wi!! expand and
overflow.
fuel consumption
A good idea is for you to rate the fuel
consumption of your snowmobile at the
first opportunity. Starting with a full fuel
tank, mark the time of your departure
then note time elapsed until tank is
half-full. Repeat on different occasions
to get a mean average of your snow-
mobiles' consumption and length of
''''10 ''''\6 time under varying conditions.
11

12
With Ski-Doo snowmobile engines, a
break-in period IS required
before run-
ning the vehicie at full throttle Manu-
facturer's recommendation for the
Bombardier-Rotax engine's 10 to 5
operating hours DUring
this period,
maximum throttle should not exceed %
However, brief full accelerations and
speed variations
contribute to a good
break-in Continued wide open throttle
accelerations, prolonged 'cruising'
speeds and lugging are detrimental dur-
Ing the break-In period
inspection
After the break-in period. we suggest
that each Ski-Doo snowmobile has an
inspection check. This
inspection is at
the discretion and expense of the ve-
hicle
owner
fuel Tank Quantity
Check that there IS sufficient fuel In the
tank for your trip A good habit to ac-
quire IS to refill the tank before
starting
out each day.
Sinee mixed fuel has a
tendency to
settle overnight,
agitate the fuel in the
tank by standing on the
footboards and
rocking the vehicle
from side to side
Track before first run)
Under certain climatic conditions, the
track of a snowmobile left outdoors
overnight may freeze to the ground or
snow surface Always make sure that
the
track IS free before attempting to
start the vehicle. (This procedure will
eliminate unnecessary drive beltwear)
Steering Operation
Check operation of steering mechanism
by rotating the handlebar
several times
from side to side If roughness or bind-
Ing IS felt, check for ice or snow that
may be blocking the mechanism

Throttle and Brake
Depress and release levers several
times to check that they operate easily
and smoothly. The throttle lever should
return to the idle position when re-
leased The brake lever should be fully
applied when it has minimum clearance
from the handlebar gnp (see Main-
tenance. Brake) If the levers do not re-
turn swiftly, remove cables and/or
housings and replace. Re-check lever
operation
Warning: Throttle mechanism
should be checked for free move-
ment before starting engine. Once
all components are checked and
functioning properly, you can start
your Ski-Doo snowmobile.
Emergency situations are accepted haz-
ards with any moving vehicle. A hidden
rock or stump on the trail, aburnt light
bulb while driving at night, an empty
fuel tank while miles from anywhere,
can all cause varying degrees of incon-
venience. Unlike an automobile, which
has a distinct advantage
In that service
stations are usually within walking dis-
tance, snowmobiles are specifically
designed to travel off the highways.
When the unexpected happens, the
driver often has only his own ingenuity
and that of his companions to return
home safely Fortunately, 9 out of 10
difficulties encountered on the trail can
be fixed on the
spot However, you must
carry at least a minimum assortment of
Tools and Spare Parts to enable you to
effect minor repairs.
Emergency Materials
In addition to those tools which the
manufacturer provides, you should carry
the following:
Tools: General Purpose Pliers-Adjust-
able Wrench (% /I opening)- Flashlight.
Spare Parts: Spark Plug-Drive belt-
Headlamp and Taitliqht bulbs-Throttle
Cable and HOUSing-Starting and tow-
ing
rope-Fuse (electric models)
Important: Always carry spare plugs
and drive belt Check condition of spark
plug frequently and look for signs of a
fouled or defective plug.
13

14
Warning: Ensure the gear shift laver
is in PARK position before starting
engine. Never run the engine at high
R.P.M. when the shih: lever is in
PARK or when the track of the ve-
hicle is raised off the ground.
Note: Before starting the engine make
sure the kill
button is in the released up-
per POSition
1Insert key In ignition
switch
2. Engage choke. (Choke is not neces-
sary if engine IS
warmed
3 Test throttle operation then apply
throttle lever slightly.
4. Turn ignition key clockwise until
starter engages
Caution: Do not engage starter lonqer
than 30 seconds. If engine does not
start on first try, key must be turned
back to OFF each
time Allow starter to
cool for 2
minutes before repeating
procedure
5.
Release throttle and key immedi-
ately engme has started. Disengage
choke
6
Allow the engine to warm up before
operating at full
throttle
Caution: Never operate the Ski-Doo
snowmobile
with the battery removed or
disconnected.
Amanual starter is standard
equipment
on all Ski-Doo snowmobiles If for some
reason the vehicie
cannot be started
electncally proceed as follows;
1insert key
in Ignition and turn to ON
position
2. Engage choke (Choke
IS not neces-
sary If engine is warmed up)
3. Test
throttle ooerauon then apply
throttle lever sllghti'y
4 Grasp manual starter handle firmly
and pull slowiy until aresistance
IS felt
then pull vigorously and engine will
start
Allow handle to return slowly to
Its oriqinal position If engine does not
start. repeat the procedure
Note: Do not pull starting rope to ItS
fullest extent or allow starting handle to
"fly back" to Its original position
5.
Release throttle and disengage
choke
immediately engme has started
6
Allow the engine to warm up before
operating at full throttle

Code Weekly (10 hours)
W1 Steering Mechanism
W2 Gear Box Oil Level
W3 Bogie Wheels
W4 RearAxle
Code Monthly (40 hours)
M1 Driven
Page
16
16
16
Page
17
Pulley Guard Removal
1. Tilt cab.
2. Pullout retaining clip and pullan
spring bolt to disengage pin from
bracket
3 Push pulley guard forward to disen-
gage from gear box bracket Lift from
vehicle.
Warning: Engine should be running
only when pulley guard is secured in
place.
Drive Belt Removal
1. Tilt cab and remove pulley guard.
2 Open the driven pulley, (larger pulley
most forward). Twist and push the slid-
ing haif then hold in open position
3. Pull the bottom of belt In toward the
front of the driven pulley then slip slack-
ened belt over the
top edge of the slid-
Ing half.
4 Slip the belt out from the drive pulley
(centrifugaI governor), and remove com-
pletely from vehicle by passing it be-
tween muffler and end of driven pulley
To install drive belt. reverse procedure.
Warning: Never run the engine with-
out drive belt installed. Running an
unloaded engine can prove to be
dangerous.
15

16
(W1) Steering Mechanism
USing light machine oIL lubricate the
lower steering
column bushing. Lubri-
cate the ski legs at grease fittings until
new grease appears at the
tnspecrton
plug
Drain
plug
(W2) Gear Box
Remove oil level inspection plug then
using a length of rigid wire as a dipstick.
check oil level, The gear box has an oil
capacity of approx. 10
OlS. To replenish
supply. remove filler cap then using a
funnel, pour in required amount of Ski-
000* chain case oil
(W3) Bogie Wheels
Lubricate the suspension bogie wheels
with low
temp grease. using a low pres-
sure grease gun Pump through the
grease fitting at the centre of each
wheel until new grease appears at the
Joint of inner side of shaft.
"Trademark Bombardier Limited

(W4) Rear Axle
Lubricate the rear axle with low-temp
grease Pump grease through the rear
axle fittings
Caution: Always use alow-pressure
grease gun.
(M1) Driven Pulley
With cab tilted and drive belt removed.
lubricate the driven pulley shaft as
follows
1Open the driven pulley. (Twist and
push sliding half)
2. Thoroughly clean the driven pulley
shaft.
3. Apply a light coat of
low temp.
grease on the shaft.
Note: Activate the sliding half several
times to distribute lubricant over full
length of shaft. Be careful
that lubricant
does not get on Inner halves of pulley
Always lubricate lightly and wipe off
surplus.
Drive Pulley Mechanism
Unlike other models in the Ski-Doo
snowmobile series, your Nordic
640ER
model is equipped with a drive pulley
that IS self-lubricating.
This unique lubricating action is
achieved through acrankshaft drilling
which draws adequate quantities of lu-
bricant from the engine and directs it
over the drive pulley mechanism
This system requires no manual lubrica-
tion during the snowmobiling season.
17

Carbonized
Normal
Burnt
Code
Weekiy
Page
W1 Spark Plug
i8
W2 Battery (electrolyte level) 19
W3 SuspensionSprings 19
W4 Track 19
W5 Track Tension 19
W6 Track Alignment 19
W7 Carburetor Adjustment 20
W8 Drive Belt Condition 21
W9 Drive
Chain Tension 21
W10
Steering Mechanism 21
Code
Monthly Page
M1 Battery (connections) 21
M2 Carburetor Flange Nuts 21
M3 Drive Belt Wear 21
M4 Brake 21
M5 Steering Adjustment 22
M6 Engine Head Nuts 22
M7 Engine Mount Nuts 22
M8 Vehicle General Inspect.on 22
(W1) Spark Plug
1. Unlock and remove upper access
door. Disconnect spark plug wires and
remove plugs
2. Check condition or plugs
1II Abrownish tip reflects ideal condi-
tions (proper carburetor adjust-
ment. spark plug heat range,
etc)
1II A black Insulator tip indicates foul-
ing
caused by carburetor Idle
speed mixture too rich Incorrect
fuel miXing ratio. wrong type of
spark plug (heat range), or exces-
sive Idling
@Alight grey Insulator tip indicates a
lean mixture caused by: carburetor
Idle speed mixture adjusted too
lean, wrong spark plug heat range,
incorrect fuel mixing ratio, or a
leaking seal or gasket
Caution: Havinq a spark plug with too
hot a heat range will cause serious en-
gine damage if the severity of engme
operating conditions are greater than
the plugs' Intended range
3. Check spark plug gap usmq a wire
feeler gauge. Gap must
be.020"
4. Reinstall plugs and connect wires
18 Above Items will be serviced I!1SP8CtIOfl3