Rotax 125 MAX evo Operation and maintenance manual

for ROTAX®-engines type
125 MAX evo
125 JUNIOR MAX evo
125 MINI MAX evo
125 MICRO MAX evo
Part no.: 297732 Edition: 10/2019
BRP-Rotax GmbH & Co KG | Rotaxstrasse 1 | 4623 Gunskirchen, Austria | T: [phone] | F: [phone]
www.rotax.com | www.rotax-kart.com
Installation instructions and
Operator‘s Manual

ROTAX 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo
General information
BRP-Rotax recommends products of the following companies:

For information regarding the repair of the engines 125 MAX evo/Junior MAX evo/Mini MAX
evo/Micro MAX evo contact an authorized service center or consult the workshop manual
(available on the internet at www.rotax-kart.com).
We ask to hand over this manual, the engine identity card and the product and service
registration document to the new owner in case of a change of ownership.
Preface
This document and all technical data and procedures therein are property of BRP-Rotax GmbH &
Co KG and are based on the state of knowledge at the time of publication. The manual has been
drawn up to the best of our knowledge. However, we exclude any liability.
We reserve all rights including technical modification and possibility of errors.
Reprinting, translation or copies in whole or in part, are authorized only after written permission by
BRP-Rotax GmbH & Co KG.
BRP-Rotax GmbH & Co KG reserves the right at any time to discontinue or change specifications,
prices, designs, features, models or equipment without incurring any obligations.
Engine performance may vary depending on, among other things, general conditions, ambient
temperature and altitude.

Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo Content
Page 1
Edition: October 01 2019
Table of Content
Chapter INTRO –
Chapter 1 – Engine installation
Chapter 2 – Fuel system
Chapter 3 – Electric system
Chapter 4 – Cooling system
Chapter 5 – Exhaust system
Chapter 6 – Installation of the accessories
Chapter 7 – Finishing work
BRP-Rotax
INSTALLATION INSTRUCTION

Notes
Page 2
Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo
Edition October 01 2019/Rev. 0
NOTES
BRP-Rotax
INSTALLATION INSTRUCTION

BRP-Rotax
INSTALLATION INSTRUCTION
Chapter: INTRO
Preface
For information regarding repair of the engine 125 MAX contact an authorized service
center or consult the workshop manual
(available on internet under www.rotax-kart.com).
Also check our YouTube-Channel for interesting HowTo-videos:
Figure 1.1: QR code, HowTo-videos
We ask to hand over this manual, the engine identity card and the product and
service registration document to the new owner in case of a change of ownership.
Contents
This Installation Manual contains instructions for all the installation work on the ROTAX®-
Engine Type 125 MAX evo, 125 Junior MAX evo, 125 Mini MAX evo and 125 Micro MAX
evo.
General
This document and all technical data and procedures therein are property of
BRP-Rotax GmbH & Co KG and based on the state of knowledge at the time of
publication The Manual has been drawn up to the best of our knowledge. However,
excluding any liability.
We reserve all rights including technical modification and possibility of errors. Reprinting,
translation or copies in whole or in part, are authorized only after written permission by
BRP-Rotax GmbH & Co KG.
BRP-Rotax GmbH & Co KG reserves the right at any time to discontinue or change
specifications, prices, designs, features, models or equipment without incurring obligation.
Engine performance may vary depending on, among other things, general conditions,
ambient temperature and altitude.
NOTE
The registration document and engine identity card must be provided to the final
consumer upon delivery by the authorized service center with handover date and
company stamp.
NOTE
The data entered in the registration document and/or engine identity card is
required for the verification of a warranty claim. Without a completely filled-in
engine identity card, no warranty claim will be granted.
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo INTRO
Page 1
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BRP-Rotax
INSTALLATION INSTRUCTION
NOTE
In case of participating in the ROTAX® MAX CHALLENGE (RMC) the engine
must be verified for conformity with the technical regulations and sealed. The
serial number of the seal must be entered in the engine identity card.
Symbols used
This Manual uses the following symbols to emphasize particular information. This
information is important and must be observed.
mWARNING
Identifies an instruction, which if not followed may cause injury or endanger the
life of the driver, mechanic or third party.
ATTENTION
Identifies an instruction which, if not followed may cause injury or endanger the
life of the driver, mechanic or third party.
ENVIRONMENTAL NOTE
Environmental notes give you tips on environmental protection.
NOTE
Indicates supplementary information which may be needed to fully complete or
understand an instruction.
✔Denotes a checking operation
TIP This information gives you additional advice and tips
INTRO
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Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo

BRP-Rotax
INSTALLATION INSTRUCTION
Safety information
mWARNING
Non-compliance can result in serious injuries or death!
For the best possible engine operation, compliance with the following advice regarding
installation of engine and equipment is required.
mWARNING
Non-compliance can result in serious injuries or death!
Engine operation is permitted only with equipment supplied by ROTAX®
mWARNING
Non-compliance can result in serious injuries or death!
Besides the engine-specific installation advice, also take note of information from the
respective chassis manufacturer.
Introduction
Congratulations on choosing the ROTAX engine Type 125 MAX.
The ROTAX® engine Type 125 MAX has been developed exclusively for use in Go-karts,
which must only be run on specified tracks. This product has numerous technical
innovations.
mWARNING
Non-compliance can result in serious injuries or death!
Before starting with installation and operation of the engine, observe the installation
instructions and Operator’s Manual and follow all instructions.
mWARNING
Non-compliance can result in serious injuries or death!
This engine performs better as comparable products
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo INTRO
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Edition: October 01 2019

BRP-Rotax
INSTALLATION INSTRUCTION
UNBOXING AND PURCHASED PARTS PACKAGE
By buying a ROTAX Engine, you will receive two boxes. The engine box and the accessory box.
Figure 1.2: Unboxing
Engine box
The engine box contains the pre-assembled engine with the secure sticker, which de-
scribes the run-in procedure. Take the engine out of the box.
Accessory box
The accessory box contains all required parts for running the engine. Lay down all parts,
so you have a good overview of the parts. Check, if all parts of the following table are
delivered.
INTRO
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Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo

BRP-Rotax
INSTALLATION INSTRUCTION
Figure 1.3: Accessory box
Pos. Description Check mark
1 Radiator with coolant hoses O
2 Mounting plate with ignition coil, solenoid valve and spark plug cap O
3 Battery box and wiring harness O
4 Battery charger O
5Intake silencer O
6Fuel pump with fuel hose O
7Exhaust system O
8 Manuals and engine identity card O
9Several small parts (spark plug, screws,...) O
10 Hose package for RAVE control unit O
11 ECU O
12 Carburetor O
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo INTRO
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BRP-Rotax
INSTALLATION INSTRUCTION
ENGINE INFORMATION
Engine serial number
The engine serial number is stamped on the clutch side housing-half.
Figure 1.4: Serial number of the engine, TYPICAL
INTRO
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Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo

BRP-Rotax
INSTALLATION INSTRUCTION
Information sticker
The information sticker is glued to the intake socket. It does not only prevent dust from
coming inside the engine during the transport, it also provides you with information about
the run-in procedure and general tasks you must do at the initial run of the engine.
Figure 1.5: Information sticker
Gear oil and fuel specifications
See the latest Operators Manual.
Equipment and modifications
Modifications to engine and/or equipment are not allowed.
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo INTRO
Page 7
Edition: October 01 2019

Notes
Page 8
Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo
Edition October 01 2019/Rev. 0
NOTES
BRP-Rotax
INSTALLATION INSTRUCTION

BRP-Rotax
INSTALLATION INSTRUCTION
Chapter: 1
ENGINE INSTALLATION
TOPICS IN THIS CHAPTER
Engine installation to the chassis............................................................................................................2
Attachment via engine pedestal ..............................................................................................................3
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo 1
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BRP-Rotax
INSTALLATION INSTRUCTION
ENGINE INSTALLATION TO THE
CHASSIS
Tools required:
• Allen key 8mm
• Ratchet wrench
NOTE
These instructions may differ depending on the
type of chassis. They are for general information
only
NOTE
Apply abrasive paper between the chassis and
the engine brackets to prevent the engine from
moving under racing conditions
Step Procedure
1 Install the upper part of the engine
brackets (2) to the engine (1).
2Place the abrasive tape strips (3) in
the area, where you will apply the en-
gine to your chassis.
3 Place the engine onto the frame and
pre-install the bottom engine brackets
(4) to the engine (1). Make sure not to
tighten them up now, so that the en-
gine is still movable onto the frame.
4Put the engine back as far as possible.
5Put the chain around the rear axle and
fit the chain to the front sprocket first.
6 Fit the chain also to the rear sprocket.
7Move the engine forward to tighten the
chain.
8If you adjusted the correct chain ten-
sion, use the stopper to keep the en-
gine in the correct position.
Step Procedure
9 Tighten the screws for the engine
brackets.
10 Make sure that the rear sprocket and
the front sprocket align to each other,
use a ruler to check it.
Figure 2.1: Example of Engine installation
1Engine 2Upper engine bracket
3Abrasive tape strips 4Bottom engine bracket
1
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Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo

BRP-Rotax
INSTALLATION INSTRUCTION
ATTACHMENT VIA ENGINE
PEDESTAL
When using an engine pedestal for the ROTAX® en-
gine 125 MAX evo/Junior MAX evo/Mini MAX evo/
Micro MAX evo, the engine is inclined at 0° to 15° in
the driving direction.
Step Procedure
1 Drill 4 holes (8.5 mm dia / 0.315 in. =
drill size) on the coordinates 80 mm x
102 mm / 3.15 in. x 4.016 in. in the top
plate of the pedestal suitable for the
chassis.
mWARNING
Non-compliance can result in serious injuries
or death!
When drilling the holes in the pedestal, pay atten-
tion to the advice of the chassis manufacturer.
Step Procedure
2 Connect pedestal with engine crank-
case with 4 screws M8 (min. strength
grade 8.8). Tighten screws to 24 Nm /
212 in. lb.
mWARNING
Non-compliance can result in serious injuries
or death!
Pay attention to chain alignment as advised by
chassis manufacturer.
NOTE
Do not fasten engine on chassis until chain is in
position and properly aligned and tensioned.
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo 1
Page 3
Edition: October 01 2019

Notes
Page 4
Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo
Edition October 01 2019/Rev. 0
NOTES
BRP-Rotax
INSTALLATION INSTRUCTION

BRP-Rotax
INSTALLATION INSTRUCTION
Chapter: 2
FUEL SYSTEM
TOPICS IN THIS CHAPTER
Installation and connection of the fuel pump...........................................................................................2
Installation of the Bowden cable for carburetor control...........................................................................4
Installation and connection of the carburetor ..........................................................................................6
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo 2
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Edition: October 01 2019

BRP-Rotax
INSTALLATION INSTRUCTION
INSTALLATION AND CONNECTION
OF THE FUEL PUMP
Step Procedure
1The retaining plate, rubber buffers, fuel
pump, fuel hose (with 230 mm and
1800 mm length) is already pre-
assembled.
Figure 3.1
Step Procedure
2 Install the support bracket (pos. 1) with
fuel pump on the carburetor socket us-
ing 3 screws M6x30 (pos. 2). Tighten-
ing torque 6 Nm / 53 lbf in.
Figure 3.2
1Support bracket 2Screws M6x30
TIP Facilitate the assembly of fuel hose by
slightly widening the hose end with a pair
of circlip pliers.
ATTENTION
Fuel hose can be damaged!
Avoid excessive widening of the fuel hose.
Figure 3.3
Step Procedure
3The fuel hose with 230 mm length will
be connected later to the carburetor,
see carburetor installation in section 3.
4The larger fuel hose (pos. 1) should
be connected to the fuel filter (pos. 2)
and to the fuel tank.
2
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Edition: October 01 2019
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo