Polaris 850 PRO-RMK 155 2020 User manual

FOREWORD
The information printed within this publication includes the latest product information at time of print. The most recent
version of this Service Manual is available in electronic format at www.polarisdealers.com.
This Service Manual is designed primarily for use by certified Polaris Master Service Dealer®technicians in a properly
equipped shop and should be kept available for reference. All references to left and right side of the vehicle are from
the operator's perspective when seated in a normal riding position.
Some procedures outlined in this manual require a sound knowledge of mechanical theory, tool use, and shop
procedures in order to perform the work safely and correctly. Technicians should read the text and be familiar with the
service procedures before starting any repair. Certain procedures require the use of special tools. Use only the proper
tools as specified. If you have any doubt as to your ability to perform any of the procedures outlined in this Service
Manual, contact an authorized dealer for service.
We value your input and appreciate any assistance you can provide in helping make these publications more useful.
Please provide any feedback you may have regarding this manual. Authorized dealers can submit feedback using 'Ask
Polaris'. Click on 'Ask Polaris', and then click on 'Service Manual / Service Literature Question'.
Consumers, please provide your feedback in writing to: Polaris Industries Inc. ATTN: Service Publications Department,
2100 Hwy 55, Medina, MN 55340.
Publication Printed October 2020 (PN 9850060 R02)
© Copyright 2020 Polaris Inc. All information contained within this publication is based on the latest product information at the time of publication. Due to constant
improvements in the design and quality of production components, some minor discrepancies may result between the actual vehicle and the information presented in this
publication. Depictions and/or procedures in this publication are intended for reference use only. No liability can be accepted for omissions or inaccuracies. Any reprinting
or reuse of the depictions and/or procedures contained within, whether whole or in part, is expressly prohibited. Printed in U.S.A.
2020-2021 850 AXYS™ Long Track
Snowmobile

SAFETY WARNINGS
The following signal words and symbols appear throughout this manual and on the vehicle. Your safety is involved
when these words and symbols are used. Become familiar with their meanings before reading the manual.
DANGER
DANGER indicates a hazardous situation which, if not avoided, WILL result in death or serious injury.
WARNING
SAFETY ALERT WARNING indicates a hazardous situation which, if not avoided, COULD result in death or serious
injury.
CAUTION
SAFETY ALERT CAUTION indicates a hazardous situation which, if not avoided, COULD result in minor to moderate
injury.
NOTICE
NOTICE provides key information by clarifying instructions.
IMPORTANT
IMPORTANT provides key reminders during disassembly, assembly and inspection of components.

TRADEMARKS
POLARIS ACKNOWLEDGES THE FOLLOWING PRODUCTS MENTIONED IN THIS MANUAL:
Loctite, Registered Trademark of the Loctite Corporation
Nyogel, Trademark of Wm. F. Nye Co.
Fluke, Registered Trademark of John Fluke Mfg. Co.
Mity-Vac, Registered Trademark of Neward Enterprises, Inc.
Torx, Registered Trademark of Textron
Hilliard, Trademark of the Hilliard Corporation
Warn, Trademark of Warn Industries
FOX, Registered Trademark of FOX RACING SHOX
RydeFX, Registered Trademark of ArvinMeritor
Some Polaris factory publications can be downloaded from www.polarisindustries.com, purchased from
www.purepolaris.com or by contacting the nearest Polaris dealer.

REVISION INDEX
REV DATE CHANGES
R01 09/28/2020 Initial Release
R02 12/03/2020 Added track specification for 2.75 models
FEEDBACK FORM
A feedback form has been created for the technician or consumer to provide Polaris
with an overall satisfaction rating for this service manual, provide comments on your
experience or upload pictures/video. This feedback form is viewable on a mobile
device by scanning the QR code or by clicking HERE if viewing this document
electronically.

2020-2021 850 AXYS™ Long Track Snowmobile
Service Manual
Chapter Summary
CHAPTER 1 : GENERAL INFORMATION
CHAPTER 2 : MAINTENANCE
CHAPTER 3 : ENGINE / COOLING / EXHAUST
CHAPTER 4 : ENGINE ELECTRICAL
CHAPTER 5 : FUEL SYSTEM
CHAPTER 6 : FINAL DRIVE / BRAKE SYSTEMS
CHAPTER 7 : PVT SYSTEM
CHAPTER 8 : STEERING / SUSPENSIONS
CHAPTER 9 : CHASSIS
CHAPTER 10 : BATTERY / ELECTRICAL

1
9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.1
GENERAL INFORMATION
CHAPTER 1
GENERAL INFORMATION
VEHICLE IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4
MODEL NUMBER DESIGNATION (2017 +) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4
VEHICLE IDENTIFICATION NUMBER (VIN) DESIGNATION (2017 +). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4
TUNNEL DECAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4
VEHICLE IDENTIFICATION NUMBER LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5
ENGINE SERIAL NUMBER LOCATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6
REFERENCE INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7
REPLACEMENT KEYS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7
PUBLICATION PART NUMBERS - 2020. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7
PUBLICATION PART NUMBERS - 2021. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8
SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.9
MODEL SPECIFICATIONS (MODEL YEAR 2020). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.10
2020 850 PRO-RMK 155. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.10
2020 850 PRO-RMK 155 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.12
2020 850 RMK KHAOS 155 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.14
2020 850 RMK KHAOS 155 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.16
2020 850 PRO-RMK 163. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.18
2020 850 PRO-RMK 163 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.20
2020 850 PRO-RMK 174 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.22
2020 850 SKS 155. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.24
MODEL SPECIFICATIONS (MODEL YEAR 2021). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.26
2021 850 PRO-RMK 155. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.26
2021 850 PRO-RMK 155 QD2 2.75 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.28
2021 850 PRO-RMK 155 QD2 3.0 TRACK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.30
2021 850 PRO-RMK 155 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.32
2021 850 RMK KHAOS 155 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.34
2021 850 RMK KHAOS 155 QD2 2.75 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.36
2021 850 RMK KHAOS 155 QD2 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.38
2021 850 RMK KHAOS 155 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.40
2021 850 PRO-RMK 163. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.42
2021 850 PRO-RMK 163 QD2 3.0 TRACK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.44
2021 850 PRO-RMK 163 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.46
2021 850 RMK KHAOS 163 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.48
2021 850 RMK KHAOS 163 QD2 3.0 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.50
2021 850 PRO-RMK 165 QD2 2.75 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.52
2021 850 RMK KHAOS 165 QD2 2.75 TRACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.54
2021 850 PRO-RMK 174 QD2 3.0 TRACK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.56
2021 850 SKS 155. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.58
CLUTCH SETTINGS (MODEL YEAR 2020). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.60
850 PRO-RMK 155/163 & RMK KHAOS 155 CLUTCH SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.60
850 PRO-RMK 155/163/174 & RMK KHAOS 155 3.0 TRACK CLUTCH SETTINGS. . . . . . . . . . . . . . . . . . . . .1.60

1.2 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
850 SKS 155 CLUTCH SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.60
CLUTCH SETTINGS (MODEL YEAR 2021). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.61
850 PRO-RMK / RMK KHAOS (155/163/165) CLUTCH SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.61
850 PRO-RMK / RMK KHAOS (155/163/174) 3.0 TRACK CLUTCH SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.61
850 SKS 155 CLUTCH SETTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.62
MISC SPECIFICATIONS AND CHARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.63
MASTER TORQUE TABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.63
CONVERSION TABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.68
SAE TAP / DRILL SIZES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.69
METRIC TAP / DRILL SIZES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.69
DECIMAL EQUIVALENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.70
FUEL RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.71
SERVICE PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.72
GENERAL DIAGNOSTICS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.73
DIAGNOSTIC TROUBLE CODES (DTCS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.73
TROUBLESHOOTING – ENGINE WILL NOT START . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.82
PERFORMANCE TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.83
DIGITAL WRENCH DIAGNOSTIC SOFTWARE OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.85
DIGITAL WRENCH SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.85
DIGITAL WRENCH SOFTWARE VERSION / UPDATE ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.86
DIGITAL WRENCH – UPDATING SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.86
DIGITAL WRENCH® COMMUNICATION ERRORS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.87
DIGITAL WRENCH® FEATURE MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.88
DIGITAL WRENCH – SYSTEM CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.89
DIGITAL WRENCH – DIAGNOSTIC TROUBLE CODES (DTCS) DISPLAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.90
DIGITAL WRENCH – DATA LIST DISPLAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.91
DIGITAL WRENCH – METERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.91
DIGITAL WRENCH – DATA TRIGGER (FREEZE FRAME) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.92
DIGITAL WRENCH – SPECIAL TESTS MENU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.93
DIGITAL WRENCH – VEHICLE HISTORICAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.93
DIGITAL WRENCH – OUTPUT STATE CONTROL TESTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.94
DIGITAL WRENCH – SERVICE REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.95
DIGITAL WRENCH – ECU / INJECTOR / OIL PUMP REPLACEMENT MENU . . . . . . . . . . . . . . . . . . . . . . . . . .1.96
DIGITAL WRENCH – ECU REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.96
DIGITAL WRENCH – FUEL INJECTOR REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.100
DIGITAL WRENCH - ELECTRONIC OIL PUMP FLOW OFFSET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.102
DIGITAL WRENCH - SERVICE PROCEDURES MENU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.104
FUEL INJECTOR BREAK-IN TIMER RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.104
OIL PUMP ENRICHMENT MODE TIMER RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.106
EV ACTUATOR LEARN PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.107
GEARING CHANGE REPROGRAMMING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.110
ELECTRONIC OIL PUMP PRIME PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.111
DIGITAL WRENCH – ECU REPROGRAMMING (REFLASH). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.113
DIGITAL WRENCH – VEHICLE IDENTIFICATION INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.116
POLARIS MOBILE DIGITAL WRENCH® (PMDW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.119
DRIVE BELT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.120
DRIVE CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.120
GENERAL INFORMATION

9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.3
DRIVEN CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.120
BELT WEAR / BURN DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.121
SHOCK ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.122
ELECTRICAL SERVICE NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.123
DIGITAL MULTI-METER (DMM) NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.123
STATIC AND DYNAMIC TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.123
CONNECTOR PROBING GUIDELINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.124
TESTING CONTINUITY / RESISTANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.125
TESTING FOR A SHORT TO GROUND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.125
TESTING FOR A SHORT TO VOLTAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.126
TESTING FOR INTERMITTENT CONDITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.127
TESTING CURRENT FLOW (AMPERAGE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.127
CURRENT DRAW - KEY OFF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.128
TESTING VOLTAGE DROP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.128
GENERAL INFORMATION
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1.4 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
VEHICLE IDENTIFICATION
MODEL NUMBER DESIGNATION (2017 +)
Example: S17SJA5BEA
GROUP MODEL YEAR MAKE LINE TYPE ENGINE SIZE /
MODIFIER MARKET OPTION
1st 2nd 3rd 4th* 5th* 6th* 7th* 8th* 9th 10th**
S 1 7 S J A 5 B E A
* = digits that would transfer to 17 digit VIN and are used in digits 4 - 8 respectively
** = 10th digit will be used on color / featured versions of models (not including the base)
First 3 digits, 9th digit and 10th digit are used in model number only. They are not used with the 17 digit VIN.
Digits 1 through 8 determine Digital Wrench calibration.
VEHICLE IDENTIFICATION NUMBER (VIN) DESIGNATION (2017 +)
Example: SN1CBA8G0G3000000
WORLD MFG.
ID
VEHICLE DESCRIPTORS VEHICLE IDENTIFIERS
MAK-
ELINE TYPE ENGINE
SIZE
ENGINE
MODIFIER
CHECK
DIGIT
MODEL
YEAR *
MFG.
LOCATION INDIVIDUAL SERIAL NO.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
S N 1 C B A 6 G 0 G 3 0 0 0 0 0 0
* Model Year: H = 2017; J = 2018; K = 2019; L = 2020; M = 2021
TUNNEL DECAL
The Tunnel Decal has the Model Number (1), VIN Number (2), and the Manufactured Date (3). These numbers should
be referred to in any correspondence regarding warranty, service, or replacement parts. The machine model and VIN
number identification decal is located on the right front side of the tunnel. The VIN (2) number is permanently stamped
into the tunnel. The model number is embossed on the decal.
GENERAL INFORMATION

9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.5
VEHICLE IDENTIFICATION NUMBER LOCATIONS
NOTICE
The Vehicle Identification Number (VIN) is stamped into the side of the tunnel and printed on the tunnel VIN label.
qCertification Label eEmissions Certification
wTunnel VIN / Model Number Label / Stamp
IMPORTANT
If installing an aftermarket tunnel wrap, do not cover the tunnel certification, tunnel VIN or emissions certification
labels with the wrap. If the tunnel wrap doesn’t provide an opening for these labels, remove the section of wrap where
the labels are located.
GENERAL INFORMATION
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1.6 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
ENGINE SERIAL NUMBER LOCATION
The engine serial number is located on the identification
label qon the engine case next to the recoil cover.
GENERAL INFORMATION

9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.7
REFERENCE INFORMATION
REPLACEMENT KEYS
Replacement keys can be made from the original key. To identify which series the key is, take the first two digits on the
original key and refer to the chart to the right for the proper part number.
(i.e. In this example, the first two digits are 31 which would use key blank PN 4110141.)
SERIES# PART NUMBER
20 4010278
21 4010278
22 4010321
23 4010321
27 4010321
28 4010321
31 4110141
32 4110148
67 4010278
68 4010278
PUBLICATION PART NUMBERS - 2020
YEAR MODEL MODEL NO. OWNER’S
MANUAL
2020
850 PRO-RMK 155 S20EFK8RS
9929772
INTL S20EFK8RE
850 PRO-RMK 155 3.0 Track S20EFM8RS
INTL S20EFM8RE
850 RMK Khaos 155 S20EFT8RS
INTL S20EFT8RE
850 RMK Khaos 155 3.0 Track S20EFN8RS
INTL S20EFN8RE
850 PRO-RMK 163 S20EGK8RS
850 PRO-RMK 163 3.0 Track S20EGM8RS
INTL S20EGM8RE
850 PRO-RMK 174 3.0 Track S20EHM8RS
850 SKS 155 S20EFS8RS
INTL S20EFS8RE
NOTICE
When ordering service parts be sure to use the correct parts manual.
Polaris factory publications can be found at www.polaris.com or purchased from www.purepolaris.com.
GENERAL INFORMATION
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1.8 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
PUBLICATION PART NUMBERS - 2021
YEAR MODEL MODEL NO. OWNER’S
MANUAL
2021
850 PRO-RMK 155 2.6" QD S21EFK8RS
9931274
850 PRO-RMK 155 2.75" QD S21EFK8RB
INTL S21EFK8RH
850 PRO-RMK 155 3.0" QD S21EFK8RC
INTL S21EF58RL
850 PRO-RMK 155 3.0" CC S21EFM8RC
850 RMK Khaos 155 2.6" QD S21EFT8RS
850 RMK Khaos 155 2.75" QD S21EFT8RB
INTL S21EFT8RH
850 RMK Khaos 155 3.0" QD S21EFT8RC
INTL S21EFT8RL
850 RMK Khaos 155 3.0" CC S21EFN8RC
850 PRO-RMK 163 2.6" QD S21EGK8RS
850 PRO-RMK 163 3.0" QD S21EGK8RC
850 PRO-RMK 163 3.0" CC S21EGM8RC
850 RMK Khaos 163 2.6" QD S21EGT8RS
850 RMK Khaos 163 3.0" QD S21EGT8RC
INTL S21EGT8RL
850 PRO-RMK 165 2.75" QD S21EGK8RB
INTL S21EGK8RH
850 RMK Khaos 165 2.75" QD S21EGT8RB
INTL S21EGT8RH
850 PRO-RMK 174 3.0" QD S21EHK8RC
850 SKS 155 S21EFS8RS
INTL S21EFS8RE
NOTICE
When ordering service parts be sure to use the correct parts manual.
Polaris factory publications can be found at www.polaris.com or purchased from www.purepolaris.com.
GENERAL INFORMATION

9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.9
SPECIAL TOOLS
Special tools may be required while servicing this vehicle. Some of the tools listed or depicted are mandatory, while
other tools may be substituted with a similar tool, if available. Polaris recommends the use of Polaris Special Tools
when servicing any Polaris product. Dealers may order special tools through the Polaris official tool supplier.
Bosch Automotive Service Solutions 1-800-345-2233 or https://polaris.service-solutions.com
GENERAL INFORMATION
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1.10 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
MODEL SPECIFICATIONS (MODEL YEAR 2020)
2020 850 PRO-RMK 155
Model Numbers: S20EFK8RS / S20EFK8RE
GENERAL
Width 43.5 in / 110.5 cm
Length 131 in / 33.27
Height 49.125 in / 124.7 cm
Estimated Dry Weight 415 lb / 188 kg
439 lb / 199 kg (Electric Start)
Fuel Capacity 11.5 Gal. / 43.5 L
Oil Capacity 3.9 Qt. / 3.7 L
Cooling System Capacity 5.3 Qt. / 5.0 L
Brake Fluid DOT 4
DRIVE BELT
Part Number 3211216
Width 1.47 in / 3.73 cm
Side Angle 28°
Circumference 46.77 in / 118.8 cm
Center Distance 11.5 in / 29 cm
QUICKDRIVE
Center Distance 7.76 in / 19.71 cm
Gearing SEE CLUTCHING SETTINGS
Reverse System Electronic Reverse
GENERAL INFORMATION

9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.11
ENGINE SPECIFICATIONS
Engine Type Patriot Liquid-Cooled /
Case Reed Induction
Model Number S6031-8444-LP8R
Displacement 840 cc
Number of Cylinders 2
Bore & Stroke 85 x 74 mm
Operating RPM ± 150 8250
Idle RPM ± 200 1800
Engagement RPM ± 200 3800
Thermostat Opening
Temperature 80-87 ° F / 29.7-30.6 ° C
FUEL SYSTEM
Type - Number of Fuel
Injectors DC-CFI - 2
Throttle Body Marking 1205875
Throttle Body Bore 50 mm
TPS Voltage @ Idle
(Using Digital Wrench) 0.86 +/- 0.05 VDC
Fuel Pressure 58-60 PSI / 4.0-4.1 bar
Fuel Octane (R+M/2)
10% Ethanol Mode
Premium Mode
<91 Octane
(Non-Oxygenated)
OR
87/89/91+
(Up to 10% Oxygenated)
91+
(Non-Oxygenated)
TRACK
Width 15 in / 38 cm
Length 155 in / 393.7 cm
Pitch 2.86 in / 7.26 cm
Lug Height 2.60 in. / 6.60 cm (Series 6 )
Track Tension 0.625 - 0.75 in / 1.6 - 1.9 cm
Stud Protection
Maximum Stud Length N/A
ELECTRICAL
Alternator Output
Operating Voltage
Watts @ 13.5 VDC (Total)
13.5-14.5 VDC
500
Idle Ignition Timing
(Variable - Based on RPM,
Pressure, and Temp.)
2° – 20°
Spark Plug NGK BPR9ES
Spark Plug Gap .027 in / .70 mm
FRONT SUSPENSION
Front Suspension Type AXYS RMK React
Front Shock
Walker Evans Impact-
Extruded Monotube*
or
Walker Evans Comp. Adj.
Piggyback
Front Travel 9.0 in / 22.9 cm
Ski Type Gripper
Ski Center Distance
Setup Width
36 - 37- 38in / 91.4 - 93.9-
96.5 cm
36.85 in / 93.6 cm
Overall Toe Out 1/8 - 1/4 in / 3 - 6 cm
* = Reference Steering / Suspension chapter for shock
settings.
REAR SUSPENSION
Rear Suspension Type AXYS RMK
Front Track Shock (FTS) Walker Evans Impact-
Extruded Monotube*
Rear Track Shock (RTS)
Walker Evans Impact-
Extruded Monotube*
or
Walker Evans Comp. Adj.
Piggyback
Rear Travel 16.0 in / 40.6 cm
* = Reference Steering / Suspension chapter for shock
settings.
For clutch settings; See 850 PRO-RMK 155/163 & RMK
Khaos 155 Clutch Settings page 1.60 later in this
chapter.
GENERAL INFORMATION
1

1.12 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
2020 850 PRO-RMK 155 3.0 TRACK
Model Numbers: S20EFM8RS / S20EFM8RE
GENERAL
Width 43.5 in / 110.5 cm
Length 131 in / 33.27
Height 49.125 in / 124.7 cm
Estimated Dry Weight 428 lb / 194kg
452 lb / 205 kg (Electric Start)
Fuel Capacity 11.5 Gal. / 43.5 L
Oil Capacity 3.9 Qt. / 3.7 L
Cooling System Capacity 5.3 Qt. / 5.0 L
Brake Fluid DOT 4
DRIVE BELT
Part Number 3211216
Width 1.47 in / 3.73 cm
Side Angle 28°
Circumference 46.77 in / 118.8 cm
Center Distance 11.5 in / 29 cm
CHAINCASE
Center Distance 7.76 in / 19.71 cm
Gearing SEE CLUTCHING SETTINGS
Gear Lube Polaris Synthetic (30W)
Capacity 8 - 10 oz / 237 - 296 ml
Reverse System Electronic Reverse
GENERAL INFORMATION

9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc. 1.13
ENGINE SPECIFICATIONS
Engine Type Patriot Liquid-Cooled /
Case Reed Induction
Model Number S6031-8444-LP8R
Displacement 840 cc
Number of Cylinders 2
Bore & Stroke 85 x 74 mm
Operating RPM ± 150 8250
Idle RPM ± 200 1800
Engagement RPM ± 200 3800
Thermostat Opening
Temperature 80-87 ° F / 29.7-30.6 ° C
FUEL SYSTEM
Type - Number of Fuel
Injectors DC-CFI - 2
Throttle Body Marking 1205875
Throttle Body Bore 50 mm
TPS Voltage @ Idle
(Using Digital Wrench) 0.86 +/- 0.05 VDC
Fuel Pressure 58-60 PSI / 4.0-4.1 bar
Fuel Octane (R+M/2)
10% Ethanol Mode
Premium Mode
<91 Octane
(Non-Oxygenated)
OR
87/89/91+
(Up to 10% Oxygenated)
91+
(Non-Oxygenated)
TRACK
Width 15 in / 38 cm
Length 155 in / 393.7 cm
Pitch 3.0 in. / 7.62 cm
Lug Height 3.0 in. / 7.62 cm (Series 7)
Track Tension 0.625 - 0.75 in / 1.6 - 1.9 cm
Stud Protection
Maximum Stud Length N/A
ELECTRICAL
Alternator Output
Operating Voltage
Watts @ 13.5 VDC (Total)
13.5-14.5 VDC
500
Idle Ignition Timing
(Variable - Based on RPM,
Pressure, and Temp.)
2° – 20°
Spark Plug NGK BPR9ES
Spark Plug Gap .027 in / .70 mm
FRONT SUSPENSION
Front Suspension Type AXYS RMK React
Front Shock
Walker Evans Impact-
Extruded Monotube*
or
Walker Evans Comp. Adj.
Piggyback
Front Travel 9.0 in / 22.9 cm
Ski Type Gripper
Ski Center Distance
Setup Width
36 - 37- 38in / 91.4 - 93.9-
96.5 cm
36.85 in / 93.6 cm
Overall Toe Out 1/8 - 1/4 in / 3 - 6 cm
* = Reference Steering / Suspension chapter for shock
settings.
REAR SUSPENSION
Rear Suspension Type AXYS RMK
Front Track Shock (FTS) Walker Evans Impact-
Extruded Monotube*
Rear Track Shock (RTS)
Walker Evans Impact-
Extruded Monotube*
or
Walker Evans Comp. Adj.
Piggyback
Rear Travel 16.0 in / 40.6 cm
* = Reference Steering / Suspension chapter for shock
settings.
For clutch settings; See 850 PRO-RMK 155/163/174 &
RMK Khaos 155 3.0 Track Clutch Settings page 1.60
later in this chapter.
GENERAL INFORMATION
1

1.14 9850060 R02 - 2020-2021 850 AXYS™ Long Track Snowmobile Service Manual
© Copyright Polaris Inc.
2020 850 RMK KHAOS 155
Model Numbers: S20EFT8RS / S20EFT8RE
GENERAL
Width 43.5 in / 110.5 cm
Length 131 in / 33.27
Height 49.125 in / 124.7 cm
Estimated Dry Weight
420 lb / 188 kg
442 lb / 200.5 kg (Electric
Start)
Fuel Capacity 11.5 Gal. / 43.5 L
Oil Capacity 3.9 Qt. / 3.7 L
Cooling System Capacity 5.3 Qt. / 5.0 L
Brake Fluid DOT 4
DRIVE BELT
Part Number 3211216
Width 1.47 in / 3.73 cm
Side Angle 28°
Circumference 46.77 in / 118.8 cm
Center Distance 11.5 in / 29 cm
QUICKDRIVE
Center Distance 7.76 in / 19.71 cm
Gearing SEE CLUTCHING SETTINGS
Reverse System Electronic Reverse
GENERAL INFORMATION