Polaris TX Starfire User manual

OWNERS TECHNICAL MANUAL
$3 :50 '

INTRODUCTION
The following pages of this manual cover one of the most
sophisticated high performance snowmobiles on the market
today.
The 1973 TX Starfire snowmobile ---"a finely
tuned, quality performance machine that is backed by a
heritage
of leadership which is unique in the industry."
The 1973 TX Starfire and this manual are the results of the
Polaris
Race Team joining forces with the newly formed
"Polaris Competitive Snowmobile Engineering Department".
This manual covers not only technical and service information
but a certain amount of theory related to the contents enclosed.
All information and specifications are printed to the best of
our knowledge at this time. "Changes and adjustments usually
are required
after meeting our competition and to suit various
track
conditions" so there can and will be some changes to
this manual. To enable us to send this new information to you
it is essential that the tear-out card in the back of this manual
be filled
out in full andmailed to Polaris.
Good luck andsuccessful racing
to all of you.
Competitive Snowmobile
Eng. Dept.
POLARIS
A Textron Company
Roseau, Minnesota 56751

TABLE OF CONTENTS
General Dimensions . . .
Specifications . . . . .
Controls
And Instruments .
Brakes . . . .
Gearing . . . . .
Chaincase Oil Level .
Clutch Alignment
And Center Distance
Steering . . . .
Tracks
And Studding
Track Alignment And Tension
Track Alignment .
Track Removal
Suspension .
Drive Belt . .
Drive Clutch .
Clutch Specifications
Trouble Shooting -Drive Clutch
Driven Clutch . . . . . . .
TX Starflame Engines . . . .
TX Starflame Engine Specifications.
General Engine
Information And Maintenance
TX Starflame Torque Patterns
Twin Cylinder Ignition . . . . . . .
Kokusan-Denki Breakerless Flywheel . .
Trouble
Shooting- Twin Cylinder Ignition
Circuit Checking Of CDI Unit By Tester .
Three Cylinder
Ignition . . . . . . .
Trouble Shooting
Of Three Cylinder Ignition
Circuit Checking Of CDI Unit By Tester
Machine Wiring Diagram . . . .
Mikuni Carburetors And Fuel Pump
Fuel Pump . . . . . . . . .
Carburetors
Keihin Carburetors -Schematic
View .
Service Instructions . . . . . . .
Float Level . . . . . . . . . .
Trouble
Shooting- Keihin RD38 And RD50
Warranty
Safety
.7
.8
.9
10. 11
12- 13
14
15
16
17- 18
19
20
22-24
25-26
27
28-30
31
32
33
34-35
36
37-39
40
41
42-46
48-49
50
51-60
62-63
64
65
66
67-68
69-77
78
79-82
83
84-85
86
87

GENERAL DIMENSIONS
Below are the general dimensions of the 1973 TX Starfire. You
will note that the styling and some important dimensions have
changed. These changes were made to further improve the
handling characteristi cs of this machine.
As compared to the 1972 Polaris TX Starfire the '73 chassis is
6" longer (Note 'A'). This is required for improved turning
and handling. The ski stance for '73 is 3" wider for better
stability (Note 'B') and more precise steering control on tight
corners.
7

p--
l
SPECIFICATIONS
The specifications on this page are very general. More detailed
specifications
will be covered under each separate item.
ITEM
294 335 439 649
TX Starflame Number
of Cylinders 2 2 3
Engine
Bore 58mm 62mm 58mm 67.75mm
Stroke 55. 6mm
55.6mm 55.5mm 60mm
Carburetor Mikuni
Mikuni Keihin Keihin
VM34 VM36 RD38 RD50
Displacement 293.79cc 335.7cc 439.9cc 648.8cc
Material Aircraft Aluminum
Chassis Overall Length
106" 106" 106"
106"
Overall Width
37"
37"
37"
37"
Overall Height
34" 34" 34" 34"
Weight
Track Track Width
15" 15 " 15" 15"
Track Material Rubber
with machine riveted cleats or molded rubber
Standard gear ratio
13.35 16.39 16.35 17.35
Ignition Type
Kokusan Capacitor Discharge
Timing Specs (5000 3.5mmBTDC 3.5mmBTDC 3.5mmBTDC 3.75mmBTDC
RPM)
26"
26"
26" 26"
*Spark Plugs
(Champion) N57 N57 N57 N57
Plug Gap
.018"
.018"
.018" .018"
Fuel System Tank Capacity 3.5
U.S. Gal . 3.5 U.S. G•l. 3.5
U.S. Gal. 3.5 U.S. Gal.
Fuel Type Premium, not less than
98 octane
Mixing Ratio 16: 1 Four gallons to one quart
Brakes
Type Hydraulic Disc Brakes
Disc Diameter
7l4" 7l4" 7l4" 7l4"
Fluid Type Automotive Hydraulic Brake Fluid
Suspension Type Equaliberator Slide Rail
*Machines come equipped from factory with Champion N59G
Spark plugs. Use these plugs for break-in ONLY. After break-
in, install N57 Champion Spark
Plugs.
8

CONTROLS AND INSTRUMENTS
The controls and instruments on your 1973 TX Starfire are
located in the position we feel is most convenient. We do
recommend, however, that each person relocate his or her
throttle and brake levers to positions better suiting the
individual's driving style for maximum control and safety.
WARNING: The brake lever is part of the master cylinder
assembly and will not function properly if
rotated more than 10° up or down from the
factory assembly position.
ft ____ ,
®- ...
I
1. Shut-off Switch 5. Tachometer
2. Gas Cap 6.
Tether Switch
3. Master Cylinder 7. Handle Bar Padding
4. Brake Control
8. Throttle Control
9

BRAKES
As performance and the new design are at the ultimate on the
'73 TX Starfire, it was necessary to incorporate a different
hydraulic brake system. This is the Kelsey Hayes caliper
system with a 7 3/4" diameter disc and the standard Polaris
master cylinder.
This system is very simple, but does need to be inspected
periodically.
Before each race, we strongly recommend that the following
be inspected:
1. Check brake hoses and fittings for signs of abrasion and
leakage.
2. Check fluid level in master cylinder. If low, use ONLY
an automotive type hydraulic disc brake fluid. This is
available from automotive supply houses or from Polaris.
Do not use hydraulic oil, mineral oil, aviation fluids, or
any red fluids.
3. Check brake handle for a solid 'squeeze'. If action feels
spongy, air has possibly entered the system and the
system
will have to be bled.
10

BRAKES (Can't.)
Bleeding the Hydraulic Brake System
To bleed the system, the following method should be followed.
1. Remove master cylinder reservoir cover and fill to top lip
of reservoir. Refer to Fig. 1, Item A.
2. Slip rubber tube over ball of top bleeder valve to direct
fluid away from painted surfaces. Refer to Fig. 2, Item A.
3. Squeeze brake lever (slowly) a full stroke and hold; to
release air through tube, unscrew top bleeder valve 3/4
turn. Close bleeder valve, then release brake lever. Repeat
above procedure until fluid flows from bleeder valve in a
solid stream that is free of air. Check master cylinder res-
ervoir periodically to make sure that it contains fluid.
Fig. 1
Fig. 2
11

GEARING
The selection of the proper chain sprocket ratios are essential
to achieve maximum performance. Track condition, snow con-
ditions, temperatures, weather, altitude, driver weight, etc. are
some of the factors which must be considered in the selection
of the proper ratio.
Your 1973 TX Starfire performance machine comes equipped
with the following sprocket ratios:
Machine 294 335 440 650
Gears 13-35 16-39 16-35 17-35
Chain pitch
Optional sprockets are as follows:
Number of teeth Polaris Part Number
12 3221020
13 3221012
14 3221023
15 3221008
16 3221021
17 3221009
19 3221010
21 3222008
23 3222017
35 3222021
39 3222026
41 3222025
The following sprocket to gear ratio chart wi II be a great benefit
to you when selecting the proper combination.
12

Sprocket
Combination
23 -35
21 - 35
23 - 39
23 - 41
19-35
21-39
21 - 41
17 - 35
(650)
19-39
19 - 41
16 - 35
(440)
17 - 39
15-35
17 - 41
16 - 39
(335)
14-35
16 - 41
15 - 39
13 - 35
(294)
15 - 41
14 -39
12 - 35
14-41
13 - 39
13 - 41
12- 39
12-41
....
l:
'El
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....
3:
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GEARING
Ratio Chain
Pitch
1.52 66
1.67
64
1.70 68
1.78 68
1.84 64
1.86
66
1.95 68
2.06 62
2.05 66
2.16
66
2.19 62
2.30
64
2.32 62
2.41
66
2.42 64
2.50
62
2.56
66
2.60 64
2.70
60
2.73
66
2.79 64
2.91
60
2.93 64
3.00
64
3.18 64
3.25 62
3.42 64
13
Chain Part
Number
3224020
3224019
3224~21
3224021
3224019
3224020
3224021
3224018
3224020
3224020
3224018
3224019
3224018
3224020
3224019
3224018
3224020
3224019
3224017
3224020
3224019
3224017
3224019
3224019
3224019
3224018
3224019

CHAINCASE 01 L LEVEL
The drive chain within this model is constantly immersed in
oil. Maintain oil level with No. 10 weight non-detergent engine
oil. We recommend that chaincase oil be checked on a weekly
basis. The proper amount of oil is % pint (237cc) in an empty
case.
DRIVE CHAIN TENSION
To maintain lasting chain and sprocket life the drive chain
tension
is very important. Chain tension should be checked on
a weekly
basis. The proper tension is %" free play at driven
sheave rim (see diagram). To tighten chain loosen lock nut and
turn tightner bolt clockwise and lock. To loosen reverse above
procedure.
14

CLUTCH ALIGNMENT AND CENTER DISTANCE
Due to the lower center of gravity location of the engine the
center distance between the center
of the crankshaft and the
center
of the jackshaft is not adjustable. Should the distance
change,
it will be necessary to inspect the mounts and mounting
bolts for proper tightness, distortion, or breakage.
+1 /8"
The proper center distance is 10~" -1/4".
+1 /32"
The sheave offset is 5/8" -0" . This is adjusted by either
adding
or removing the spacer washers from behind the driven
clutch.
After alignment, you should very carefully start the engine,
accelerate the machine to get the belt to the top of the drive
clutch and make certain the belt is running in a straight line.
Clutch center distance and alignment should
be checked
0 weekly or immediately after a belt is replaced.
WARNING: Do not rev engine above level required to get
belt to top of drive clutch when in unloaded
condition (approximately 7500 RPM). Stay
clear
of all moving parts.
15

STEERING
Your 1973 TX Starfire performance snowmobile comes equip-
ped with carbide ski skags for more precise high speed hand-
ling. These new skags exert a greater amount of force not only
on the skag itself but also on the entire steering assembly.
We recommend that to achieve maximum life from the skag
that you tack weld this skag to the ski board in addition to
the bolts.
For your own safety and reliability, it is important that weekly
all nuts, bolts, and tie rod ends
be checked for looseness or
stress damage.
Ski tow-in should be checked at the same time. Skis should be
parallel when in the straight ahead position to each other to
3/8" toe-out.
WARNING: Never operate your 1973 Starfire with skis
toed-in
or your 'Polaris may set you free.'
If adjustment is required:
1. Release tie rod end locknuts.
2. Rotate tie rod until alignment is correct.
3. Tighten locknuts.
4. In the event that any of these items are damaged
or overstressed, we recommend replacement of com-
plete tie rod and rod end bearings in sets.
16
31 +3/8
- 0

TRACKS AND STUDDING
Your 1973 TX Starfire performance snowmobile wi. l'l come
equipped
with either the performance cleated track· or the
long distance molded rubber track, as ordered.
The performance cleated track
is equipped with nine (9)
'Talonic Cleats', eighteen (18) Guide Cleats and ten (10)
Standard Cleats.
Ice studs
are not necessary.
Although the nine (9) Talonic Cleats are sufficient for most
conditions,
it will be necessary to add or remove some of these
cleats depending on the track and conditions you are running
on.
IMPORTANT!! After every day of racing check track mate-
rial, cleats, and rivets for damage or break-
age; replacing when necessary.
WARNING: The rivets used for holding on the cleats on
Starfire model
are of a different alloy than
those
used on all other Polaris models. It is
essential that when installing new rivets to use
the ones specified for the TX Starfire. These
are available fr om Polaris by ordering part
number 7621430.
IYET #7621430
17

TRACKS AND STUDDING (Con't.)
The long distance molded rubber track is a proven track for
your long distance endurance races and is equally good on the
oval.
This track comes without ice studs installed because many
people have their own ideas of which stud is the best. How-
ever, we do recommend the carbide tipped ice stud available
from:
Special Sports Products Corporation
1573 Pinecrest Drive
Cario, Michigan 48723
Roetin Industries
24 Saginaw Drive
Rochester, New
York 14623
and many other
sources.
The recommended pattern for studding this track is shown in
the diagram below.
18