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Kubota KX121-3, KX161-3 Excavator Workshop Repair Manual

Kubota KX121-3, KX161-3 Excavator Workshop Repair Manual

$34.00

🚜 Equipment
Brand	Kubota
Type	Excavator
Model	KX121-3, KX161-3
📄 Documents
Type	Repair Manual
Publication	97899-60550
Language	English
Format	PDF
No of Pages	994

The Kubota KX121-3 and KX161-3 Mini Excavators are powerful and efficient compact machines designed to handle mid-range to heavy-duty excavation, trenching, and utility tasks. Built with Kubota’s proven diesel engines and advanced load-sensing hydraulic systems, they deliver superior digging performance, fuel efficiency, and operator comfort, making them highly reliable for construction and landscaping operations.

The KX121-3, with an operating weight of approximately 4.1 tonnes, is powered by a 42 hp Kubota V2203-M engine. It offers a maximum digging depth of about 3.5 meters and a reach of 5 meters, with a transport width of 1.7 meters for maneuverability on confined job sites. The KX161-3, a larger model weighing about 5.2 tonnes, is equipped with a 47 hp Kubota V2403-M engine. It achieves a maximum digging depth of 4 meters and a reach of 6 meters, with a wider transport width of 1.96 meters for greater stability during demanding operations. Both models are designed with ROPS/TOPS-compliant cabs, ergonomic controls, and efficient auxiliary hydraulics for versatile attachment use.

The workshop repair manual provides complete coverage of both models, including general servicing, safety precautions, engine specifications, hydraulic systems, travel and swing motors, swivel joints, control valves, electrical circuits, and cab assemblies. It features detailed diagrams, wiring and hydraulic schematics, torque specifications, lubrication intervals, troubleshooting procedures, and step-by-step disassembly and reassembly instructions. Optional coverage includes air conditioning systems, angle dozer attachments, and advanced electrical diagnostics (AI-version).

Key Highlights

KX121-3: ~4.1 t operating weight, 42 hp Kubota V2203-M engine, ~3.5 m digging depth, ~5 m reach
KX161-3: ~5.2 t operating weight, 47 hp Kubota V2403-M engine, ~4 m digging depth, ~6 m reach
Transport widths: 1.7 m (KX121-3) and 1.96 m (KX161-3) for access and stability
Load-sensing 3-pump hydraulic system for efficient operation
Bucket breakout forces exceeding 9,000–11,000 lbs depending on model
ROPS/TOPS-compliant cabs with ergonomic controls and climate control options
Manual covers engine, hydraulics, swing/travel motors, swivel joints, electrical systems, and cab equipment
Includes detailed wiring/hydraulic schematics, torque values, lubrication guides, and troubleshooting flowcharts
Optional sections on air conditioning units, angle dozer attachments, and advanced AI-version diagnostics
Designed for long-term durability, efficient servicing, and safe operation

Table of Content

📙 Table of Contents

Wsm_Kx-121-3_161-3

WSM_KX-121-3_161-3
- CONTENTS
- I. General
  - A. Body and engine identification marks
  - B. Safety precautions for servicing, disassembly and reassembly
    - a. Safety measures before starting work
      - (1) Work clothes
      - (2) Inspecting equipment and tools
      - (3) Keep workshop in order
    - b. Safety measures during work
      - (1) Protectors
      - (2) Team work
      - (3) Disassembly and assembly
      - (4) Cranes
      - (5) Others
    - c. Preparation for disassembly
      - (1) Cleaning
      - (2) Acceptance inspection
      - (3) Equipment and tools
    - d. Precautions for disassembly and reassembly
      - (1) Disassembly
      - (2) Reassembly
  - C. IMPORTANT SAFETY PROCESS AND CRITICAL FUNCTIONAL PROCESS
    - a. Essential Adhesives
    - b. Important Safety Process.
    - c. Important Critical Functional Process.
  - D. IMPORTANT INSPECTION ITEMS AFTER REASSEMBLING
    - a. Operate the Machine and check for Unusual Noise and Vibrations.
    - b. Make Sure the Safety decals and Wire harness Clamps are in their Specified Positions.
    - c. With the Machine Front in a Specified Posture, Check the Amount of Hydraulic Oil
  - E. SERVICING FUNDAMENTALS
    - a. Items for Servicing
    - b. O-ring, Oil seal, Circlip and Roll Pin
    - c. Piping
      - (1) General precautions
      - (2) Hydraulic hose
      - (3) Precautions in tightening the bolts and nuts
      - (4) Hose screw
      - Metric Size Hose
      - (5) Joint bodies
      - (6) Tightening torque table for hose clamp (Screw type)
      - (7) Nuts for piping
      - (8) Tightening torque of bolts and nuts
      - (9) Types and materials of bolts and nuts
      - (10) Washer-equipped elbow
      - Machine Quality Specifications
      - KX121-3, 161-3 : KTC, KCL, KTA Version
  - F. Maintenance intervals
    - a. KTC, KCL, KTA-version
    - b. EU-version
    - c. Hydraulic Oil Check for machines with Hydraulic Breakers
  - G. Water and oil quantity
  - H. Recommended oil
  - I. Filters
  - J. Compatibility Table of main components between U45-3. and KX121-3, 161-3
- II. Machine body (Mechanism section)
  - A. Product Feature
    - a. A New Load Sensing System.
      - Upgraded basic performance -work efficiency
    - b. Low Operating Cost, Easy To Service
    - c. Built For Tough Work, Not Tough On The Operator.
  - B. Standard equipment
  - C. Machine specifications
    - a. KX121-3 EU-version
    - b. KX161-3 EU-version
    - c. KX121-3 KTC, KCL, KTA-version
  - D. Component interchangeability
    - a. Bucket interchangeability
    - b. Arm
  - E. Machine structure
    - a. Front attachment : KX121-3, EU-version
    - b. Seat & control box
    - c. Control linkage
    - d. Engine mount : KX161-3
    - e. Undercarriage : KX121-3
    - f. Rubber track
    - g. Iron track
    - h. Track conversion : KX121-3
      - Between rubber track and iron track
- II. Machine body (Service section)
  - A. Specifications
    - a. Machine Weight
      - (1) KE, KDG, KUK version
      - (2) KTC, KCL, KTA version
    - b. Machine specifications
      - (1) KE, KDG, KUK version
      - (2) KTC, KCL, KTA version
    - c. Lever stroke and operating force
      - (1) KE, KDG, KUK version
      - (2) KTC, KCL, KTA version
    - d. Dimensions of Parts
      - (1) Front pins
      - (2) Bucket
      - (3) Rubber crawler
      - (4) Iron crawler
      - (5) Track toller, idler, sprocket
      - (6) Dozer
      - (7) Parts weight
      - (8) Water and Oil Quantity
  - B. Front attachment
    - a. Parts designation
    - b. Exchange of bucket (Kubota Japan Bucket)
    - c. Exchange of bucket teeth and side cutter
    - d. Installing direction of dust seal
    - e. Installation of thrust collar on the swing bracket
    - f. Installing pin, bush and shim (1): KX121-3, KX161-3
    - g. Installing pin, bush and shim (2): KX121-3, KX161-3
    - h. Installing pin, bush and shim of bucket: KX121-3, KX161-3
    - i. Installing local bucket : KX121-3, KX161-3
    - j. Greasing points
    - k. Front hoses and clamps : KX121-3, KX161-3
    - f’. Installing pin, bush and shim (1): KX161-3 KTC, KCL, KTA
    - g’. Installing pin, bush and shim (2): KX161-3, KTC, KCL, KTA
    - h’. Installing pin, bush and shim of bucket: KX161-3, KTC, KCL, KTA
    - l. Installing direction of fixing pin bolts : KX121-3
  - C. Upper Structure
    - a. Swivel bearing
    - b. Pilot control lever : KX121-3, KX161-3
    - c. Traveling lever : KX121-3, KX161-3
    - d. Traveling lever adjustment : KX121-3, KX161-3
    - e. Traveling lever lock : KX121-3, KX161-3
      - Adjusting the lever’s neutral position
    - f. Accelerator lever : KX121-3, KX161-3
      - (1) KE, KUK, KDG version
      - (2) KTC, KCL, KTA version
    - g. Dozer lever : KX121-3, KX161-3
      - (1) EU version
      - (2) KTC, KCL, KTA version
      - (3) KX161-3 : KTC, KCL, KTA version
    - h. TPSS lever : KTC, KCL, KTA-version : KX121-3
    - i. Swing & SP pedal : KX121-3, KX161-3
    - j. Control valve links : KX121-3, KX161-3
    - k. Limit switch installation : KX121-3, KX161-3
    - l. Control stand
    - m. Control stand : KX121-3
    - n. Installing weight : KX121-3, KX161-3
    - o. Installing covers : KX121-3, KX161-3
  - D. Cab installation : KTC, KCL, KTA-version
    - a. Mounting bolt
    - b. Seal rubber
    - c. Wiper : KTC, KCL, KTA-version
    - d. Heater hose : KTC, KCL, KTA-version
    - e. Wire harness : KTC, KCL, KTA-version
    - f. Cab glass replacement procedure
      - (1) Application Procedure if SIKAFLEX (ULTRA-FAST)
      - (2) ULTRA-FAST application manual
      - (3) 255 EXTRA application manual
      - (4) H-rubber replacement procedure
      - (5) Broken glass repairing procedure (for adhered glass KX-2 Series made by KBT)
    - g. Defroster hose : KTC, KCL, KTA
    - h. Defroster hose : EU
  - E. Under carriage
    - a. Track tension device : KX121-3, 161-3
    - b. Track sag distance
    - c. Crawler installation
    - d. Track Roller and Upper Roller installation
- III. Engine
  - A. Specifications & features
    - a. Technical data : KX121-3, KX161-3
    - b. Performance curve
    - c. Features
    - d. Structure and function
      - (1) Fuel injection pump
      - (2) Coupling flange
      - (3) Fuel filter
      - (4) Air filter
      - (5) Thermostat
  - B. Engine mounting procedure : KX121-3
    - a. Engine mount
    - b. Air cleaner : KX121-3, KX161-3
    - c. Radiator : KX121-3, KX161-3
    - d. Muffler : KX121-3, KX161-3
    - e. Pump coupling
    - f. Fuel tank installation : KX121-3, KX161-3
    - g. Fuel tank cushion : KX121-3, KX161-3
    - h. Fuel hoses : KX121-3, KX161-3
    - i. Accel cable and meter cable
  - C. 03-M series Engine WSM
- IV. Hydraulic system (Mechanism section)
  - A. Features of hydraulic system
    - EEE hydraulic system
    - (1) Three big features
    - (2) New Hydraulic System Features
    - (3) Component of new hydraulic system
    - (4) Circuit comparison between New Hydraulic System and conventional systems
    - (5) Feature 1. High Efficiency
    - (6) Feature 2. Easy operation
    - (7) Feature 3. Economy
  - B. Hydraulic system specifications
  - C. Main pump
    - a. Structure & performance curve
    - b. Operating principle
      - (1) Variable displacement pump
      - (2) Power control
      - (3) Load sensing control
      - (4) Gain control
      - (5) Standby Flow
  - D. Control valve
    - a. Specifications
    - b. General view of control valve
    - c. Control valve circuit diagram
    - d. Operating principle
      - (1) Unload valve
      - (2) High-pressure selector valve
      - (3) Pressure compensating valve
      - (4) Boom anti-drift valve
    - e. Automatic air bleeding in hydraulic pilot section
      - (1) When the spool of the control valve is at neutral position.
      - (2) When the spool of the control pilot valve is moved in full stroke.
    - f. Relief valve/Anti-cavitation valve
  - E. Pilot valve
    - a. Structure & specifications
    - b. Pilot valve control diagram
      - (1) KE, KDG, KUK version
      - (2) KTC, KCL, KTA version
  - F. Swivel motor
    - a. Structure & specifications
    - b. Function of negative brake
      - (1) Negative brake function (Unload condition)
      - (2) Negative brake release (On-load condition)
    - c. Function of valve section
      - (1) Make-up valve
      - (2) Function of shockless valve
      - (3) Relief valve
      - (4) Shockless piston
      - (5) Make-up poppet
  - G. Rotary joint (Swivel joint)
  - H. Travel motor
    - a. Structure & specification
    - b. Operation of piston motor
    - c. Function of anti-cavitation valve
      - (1) Construction
      - (2) Circuit behavior
  - I. Hydraulic circuit diagram
    - a. KX121-3 European – version
    - b. KX161-3 European – version
    - c. KX121-3 KTC, KCL, KTA – version
    - d. Hydraulic components layout
    - e. KX161-3 European-version
    - f. KX161-3 KTC, KCL, KTA-version
- IV. Hydraulic system (Service section)
  - A. Troubleshooting
    - a. Case – Study : Abnormal speed
    - b. Case – Study : The power is weak.
    - c. Case – Study : Poor Manipulation and Abnormal Operation
    - d. LS control system troubleshooting
    - e. Pump component trouble causes and remedy
    - f. Control valve component troubleshooting
    - g. Travel motor component troubleshooting
  - B. Specifications
  - a. Relief valve pressure setting
  - b. Pump
  - c. Load sensing control system data
  - d. Cylinder
  - e. Swivel Performance
  - f. Traveling Performance
  - C. Testing
    - a. Testing Instruments & special tools
    - b. Precautions in handling the pump
    - c. Pilot pressure
    - d. Main relief valve
    - e. Unload valve
    - f. Overload relief valve
    - g. Swivel brake valve pressure
    - h. Measuring the main pump Max. flow rate
    - i. Measuring the main pump’s stand-by flow rate
    - j. LS control pressure
    - k. Traveling motor drain amount
    - l. Swivel motor drain amount
    - m. Swivel motor block performance
    - n. Traveling motor block performance
    - o. Operating speed
    - p. Straight travel performance
    - q. Cylinder natural fall amount
    - r. Control and Traveling lever operating force
    - s. Lever stroke
  - D. Disassembling and Assembling
    - a. Coupling flange
    - b. Pump: KX121-3, KX161-3
    - c. Control valve
    - d. Pilot valve
    - e. Swivel motor
    - f. Wheel motor : KX121-3, 161-3
    - g. Rotary joint : KX121-3, 161-3
    - h. Cylinder (KE, KDG, KUK version)
    - i. Cylinder (KTC, KCL, KTA version)
    - j. Other hydraulic device
    - k. Hoses
- V. Electrical system (Mechanism section)
  - A. Components, harness layout & coupler
  - A. Components, harness layout & coupler : KX161-3 AI-version
  - B. Circuit diagram
    - a. Electric Circuit Diagram: KX121-3, KX161-3
    - b. Functional Electric Circuit Diagram : KX121-3, KX161-3
    - c. Cab Electric Diagram : KX121-3, KX161-3
      - KTC, KCL, KTA-version
    - d. Cab Electric Diagram : KX121-3
      - EU-version
    - e. Electric Circuit Diagram : KX161-3 AI-version
    - f. Electric Wiring Diagram : KX161-3 AI-version
  - C. Function of main circuit
    - a. Battery circuit (Non-AI-version)
    - b. Safety Relay circuit (Automatic release function) Non-AI-version
      - (1) Operation
      - (2) Precaution
      - (3) Function chart of auto release controller
    - c. Auto glow circuit (Non-AI-version)
      - (1) Function
    - d. Fuel control circuit (Non-AI, AI-version)
      - (1) Function
      - (2) Engine stop solenoid (Non-AI, AI-version)
    - e. Engine oil pressure sensor circuit (Non-AI, AI-version)
    - f. Horn circuit (Non-AI, AI-version)
      - (1) Structure
      - (2) Function
      - (3) Current flow
      - (4) Horn circuit
    - g. Cab & Working lamp circuit (Non-AI, AI-version)
    - h. Meter panel (Non-AI-version)
    - i. Heater circuit (Non-AI, AI-version)
    - j. Travel hi-speed control circuit (Non-AI, AI-version)
    - k. Auto idle control system (AI-version)
      - (1) Purpose
      - (2) Auto idle function mechanism
      - (3) AI function layout
      - (4) Behavior when the control lever is returned to neutral
      - (5) Behavior when the control lever is operated:
      - (6) AI motor normal-turn circuit
      - (7) AI motor reverse-turn circuit
    - l. Battery direct line (AI-version)
    - m. Starter lock relay & auto release relay (AI-version)
      - (1) Safety start system
      - (2) Auto release function (AI-version)
    - n. Self holding relay circuit (AI-version)
    - o. Water temp. sensor circuit (AI-version)
    - p. Meter panel (AI-version)
    - q. AI controller unit (AI-version)
  - D. Structure and function of main components
    - a. Key switch (Engine starter switch)
    - b. Water temp. sensor & gauge
    - c. Fuel gauge
    - d. Safety lever lock switch, travel hi-low pedal switch
    - e. Relay
    - f. Engine speed sensor
    - g. Governor sensor
    - h. Accel sensor (Electric accelerator)
    - i. AI pressure switch
    - j. Fundamentals
    - k. Measurement
      - (1) Measurement of current
      - (2) Measurement of voltage
      - (3) Measurement of resistance
    - l. Introduction of semiconductor
      - (1) Semiconductor
      - (2) Genuine semiconductor
      - (3) Impurity semiconductor
      - (4) Diode
      - (5) Transistor
      - (6) Thyristor (SCR)
    - m. Introduction of magnetism
      - (1) Magnet & magnetism
      - (2) Magnetic line of force and magnetic field
      - (3) Magnetic action of electricity
    - n. Introduction of starter motor
      - (1) Operating Principle
      - (2) Principle of motor, Fleming’s left hand rule
      - (3) Type of starter
    - o. Introduction of generator, alternator
      - (1) Outline of Electric Generator and Charging System
      - (2) Principle of Alternator
      - (3) Small Alternator with IC Regulator
- V. Electrical system (Service section)
  - A. Wire harness installation
    - a. Precautions
    - b. Engine earth, starter switch
    - c. Main harness
    - d. Control box
    - e. Engine harness
    - f. Front harness
    - g. AI motor installation : AI-version
    - h. Control box : AI-version
    - i. Main harness : AI-version
  - B. Troubleshooting
    - a. General
      - (1) How to diagnose
      - (2) INSPECTION OF HARNESS CONNECTOR
      - (3) Inspection
      - (4) INSPECTION INSTRUMENTS
      - (5) CHECKING SWITCHES
      - (6) Checking fuses
      - (7) Solenoid test method
      - (8) Checking relays
      - (9) Checking cables and wires
      - (10) HANDLING ON-VEHICLE BATTERY
    - b. Troubleshooting flow chart
      - (1) Starter motor failure to turn on
      - (2) Auto release malfunction
      - (3) Electronic accelerator failure
      - (4) Auto glow failure
      - (5) AI system failure
    - c. Front attachment
      - (1) Working lamp failure
      - (2) Safety lever lock circuit malfunction
    - d. Engine electrical system
      - (1) Engine oil pressure failure
      - (2) Water temp. sensor circuit malfunction
      - (3) Fuel sensor circuit
      - (4) Engine stop solenoid
      - (5) Charging system malfunction
      - (6) Auto glow controller
      - (7) Auto release controller
    - e. Auto idle system
      - (1) Troubleshooting outline
      - (2) AI pressure switch test method
      - (3) Governor sensor test method
      - (4) AI motor test method
      - (5) Engine speed sensor
      - (6) Auto glow circuit
    - f. AI version: AI controller (built-in microcomputer) Cases of trouble diagnosis with circuit tester
      - (1) “Water temperature sensor” line in trouble
      - (2) Other circuitry layouts and their trouble diagnosis
    - g. Cases of trouble diagnosis with circuit tester
    - h. Auto Idle (AI) version: Trouble diagnosis with lamp
      - (1) General
      - (2) Display and identification of errors in operating mode
      - (3) Entering the service mode
      - (4) Working on the 6 menus in the service mode
      - (5) Example: Alternation of engine idling speed
      - (6) Working on the 3 menus in the service mode
      - (7) Working on the AI motor drive menus in the service mode
      - (8) Entering the setup mode
      - (9) Lamp-identified fail symptoms, trouble spots and possible causes
  - C. Electrical equipment specifications
- VI. Optional Unit : Air Conditioner (Mechanism Section)
  - A. Air Condition System
    - a. Introduction of air conditioner
      - (1) Principle of Air Conditioner
      - (2) Change of State of Refrigerant
      - (3) Function and Construction
      - (4) Refrigerant Cycle
    - b. Components and location
      - (1) Air conditioner & accessory assy
      - (2) Layout of A/C components : AI-version
      - (3) Layout of A/C components : Non AI-version
    - c. A/C system, electric circuit diagram
      - (1) Key-Off condition
      - (2) Key-ON (AC) condition
      - (3) A/C electric circuit diagram (DENSO A/C)
      - (4) Key-Off condition
      - (5) Key-ON (A/C) Conditions
      - (6) Key-ON (A/C) + A/C SW-ON Condition
      - (7) Key-ON (A/C) + A/C SW-ON + Blower SW-Low Condition
      - (8) Key-ON (A/C) + A/C SW-ON + Blower SW-Low + thermostat-OFF Condition
  - B. Function and structure
    - a. Compressor
      - (1) Outline of sliding-vane type compressor (SV07 type) : KX121-3, 161-3
      - (2) Feature
      - (3) Main specifications
      - (4) Structure & Function
      - (5) Oil Replenishment upon Function Part Replacement (for the HFC134a System)
    - b. High pressure relief valve
    - c. Magnetic Clutch
      - (1) Principle
      - (2) Magnetic Clutch
      - (3) Operation
    - d. Condenser
      - (1) Description
      - (2) Type of Condenser
    - e. Receiver
    - f. Dual Pressure Switch
      - (1) Location & structure
      - (2) When the Pressure is Abnormally High
      - (3) When the Pressure is Abnormally Low
    - g. Air Conditioner Unit
      - (1) Outline
      - (2) Expansion Valve
      - (3) Evaporator
      - (4) Heater Core
      - (5) Water Valve
      - (6) Air filter
      - (7) A/C Blower
      - (8) Gas Type Thermostat
      - (9) A/C blower resistor
    - h. Refrigerant
      - (1) Refrigerant R134a
      - (2) Refrigerant Properties
  - C. Electrical System
    - a. Electrical Circuit
    - b. Air Conditioner Blower Switch
    - c. Dual Pressure Switch
      - (1) Pressure Switch (Dual Type)
    - d. Thermostat
    - e. Control Panel
    - f. Air Flow
  - D. Technical Terms
    - a. Heat
      - (1) Specific Heat
    - b. Temperature
      - (1) Temperature Scales
      - (2) Wet Bulb and Dry Bulb Thermometers
      - (3) Dew Point Temperature
    - c. Humidity
      - (1) What is Humidity?
      - (2) Relative Humidity
      - (3) Absolute Humidity
      - (4) Check Performance of Air Conditioning System
    - d. Pressure
      - (1) Atmospheric Pressure
      - (2) Absolute Pressure
    - e. Change of State
      - (1) Stage Change of Water
      - (2) Sensible Heat and Latent Heat
      - (3) Three States of Matter
    - f. What is a Heater?
      - (1) Principle
      - (2) Temperature Control
    - g. Principle of Cooling
      - (1) Basic Theory of Cooling
      - (2) Refrigerant
    - h. Principle of Air Conditioning
      - (1) Expansion and Evaporation
      - (2) How to Condense Gaseous HFC134a into Liquid
      - (3) Condensing of the Gaseous HFC134a
    - i. Refrigeration Cycle
    - j. Practical Control of Air Conditioner
      - (1) Concept of control
      - (2) Principle of control
    - k. Mollier Diagram
    - l. Basic Operation of Cooling Cycle
    - m. Calculation of Refrigeration Capacity and Power from Mollier Diagram
    - n. Calculation of Flow of Circulating Refrigerant
    - o. Theoretical Performance (Sample Calculation)
      - (1) Compressor output ; L
      - (2) Evaporator capacity Qer ;
      - (3) Condenser capacity Qco ;
      - (4) Basically,
      - (5) Coefficient of Performance ;
      - (6) Relevant diagram
- VI. Optional Unit : Air Conditioner (Service Section)
  - A. Troubleshooting
    - a. Visual and Audible Inspection
    - b. Components
    - c. Diagnosis flow chart
    - d. Troubleshooting from Problem Symptoms (Except Refrigeration Cycle Troubles)
  - B. Servicing Specifications
    - a. Specifications of A/C system and components
    - b. Performance Specifications
    - c. Adjustment and Testing
    - d. Ambient Temperature vs Normal High-Low Pressure Range
    - e. Tightening Torques
  - C. Regular Check and Service Points
    - a. Maintenance interval ; Air conditioner
    - b. Regular Service Points
  - D. Precautions at Repairing Refrigerant Cycle
  - E. Precaution for Installation and Maintenance
  - F. Checking and Charging Refrigerant Cycle
    - a. Handling Of Service Tools
      - (1) Manifold Gauge Set
      - (2) Refrigerant Charging Hose
      - (3) Vacuum Pump Adaptor
      - (4) Electric Gas Leak Tester
      - (5) Can Tap Valve
      - (6) T-joint
      - (7) R134a Refrigerant Recovery and Recycling Machine
      - (8) Special tools
    - b. Checking with Manifold Gauge
    - c. Discharging, Evacuating and Charging
      - (1) Discharging the System
      - (2) Evacuating the System
      - (3) Charging the System
      - (4) Charging an Empty or Partially Charged System (Vapor)
      - (5) Checking Charge Refrigerant Amount
      - (6) Charging procedure of refrigerant (Summary)
  - G. Main Components Servicing
    - a. Compressor
      - (1) Checking
      - (2) Disassembling and reassembling
      - (3) Compressor dismounting
      - (4) Hub Plate
      - (5) Rotor
      - (6) Stator
      - (7) Adjustment of Air-gap
      - (8) Compressor installation
      - (9) V-belt tension
      - (10) Engine bracket 1, A/C
      - (11) Relief valve
    - b. Condenser and Receiver
      - (1) Parts location
      - (2) Installation of condenser and receiver
    - c. Air conditioner unit
      - (1) Mounting procedure
      - (2) Location of steps
      - (3) Dismounting steps
    - d. Electrical System Components
      - (1) A/C Blower Relay and Compressor Relay
      - (2) Relay specs (at 20˚C)
      - (3) A/C Blower Switch
      - (4) A/C Blower Motor Test
      - (5) A/C cooler switch
      - (6) A/C Blower Resistor
      - (7) Dual pressure switch
    - e. Heater hose and control cable
      - (1) Parts location
      - (2) Water Valve Control Cable (White Tape)
      - (3) A/C switch
    - f. Cooler hoses installation
      - (1) Handling the air-conditioner parts
      - (2) Cooler hose
      - (3) Gas charging
      - (4) Cooler hoses layout 1
      - (5) Connection of cooler hoses
      - (6) Cooler hoses layout 2
      - (7) Cooler hoses layout 3
      - (8) Hoses Layout photos
    - g. Duct cover installation
    - h. Noise absorber and trims
    - i. Labels
    - j. Wire harness route
    - k. Wire harness clamps for A/C version
    - l. Parts identification of Air conditioner version
      - (1) Changes in the engine
      - (2) Changes in the radiator and oil cooler
      - (3) Changes in the frame (arch)
      - (4) Changes in the steps
      - (5) Changes in the right-side control
      - (6) Replacing the rubber mat
      - (7) Changes in the cabin
      - (8) Replacing the bonnet frame (R)
      - (9) Replacing the left bonnet (1)
      - (10) Replacing the bonnet cover assembly (1)
      - (11) Replacing the seat support cover
      - (12) Replacing the seat mount parts
      - (13) Replacing the wire harness
      - (14) Replacing the upper cover (R)
      - (15) Replacing the battery-related parts (Only for the KX121-3US without AI(Type: 95D31R --> 80D26R))
      - (16) Compressor
      - (17) Receiver and condenser
      - (18) Air conditioner unit
      - (19) A/C switch and heater valve
      - (20) Duct
      - (21) Seat support
      - (22) Step plate
      - (23) Bonnet, left
- VII. Optional Unit (KTC) : Angle Dozer (KX121-3)
  - A. Specifications
  - B. Machine Quality Specifications
  - C. Lubrication point of angle dozer
  - D. Dozer lever
    - a. Dozer angle operation
    - b. Dozer lever, angle
  - E. Control valve
    - a. Specifications
    - b. General view of control valve
    - c. Control valve circuit diagram
    - d. Angle section
    - e. Adaptor installation
  - F. Rotary joint
    - a. Assembling of the rotary joint
    - b. Adaptor installation
    - c. Hose connection
  - G. Under carriage
    - a. Angle dozer
  - H. Hydraulic Circuit
    - a. KX121-3 Hydraulic Circuit (USA, Angle blade)

Specification

Specification	Kubota KX121-3 Mini Excavator	Kubota KX161-3 Mini Excavator
Operating Weight	≈ 4,111 kg (9,063 lb) :contentReference[oaicite:0]{index=0}	≈ 5,231 kg (11,532 lb) :contentReference[oaicite:1]{index=1}
Engine Power	42 hp net (V2203-M) :contentReference[oaicite:2]{index=2}	47 hp net (V2403-M) :contentReference[oaicite:3]{index=3}
Max Digging Depth	~3.5 m (11.5 ft) :contentReference[oaicite:4]{index=4}	~4 m (13 ft) :contentReference[oaicite:5]{index=5}
Max Reach Along Ground	~5 m (18 ft) :contentReference[oaicite:6]{index=6}	~6 m (20 ft) :contentReference[oaicite:7]{index=7}
Transport Width	~1.7 m (~5 ft 7 in) :contentReference[oaicite:8]{index=8}	~1.96 m (~6 ft 5 in) :contentReference[oaicite:9]{index=9}
Dimensions (L × H)	Length ~5.09 m (16 ft 7 in), Height ~2.49 m (8 ft 2 in) :contentReference[oaicite:10]{index=10}	Width, reach, height unspecified; see digging/reach specs :contentReference[oaicite:11]{index=11}

Buyer Questions & Answers

Frequently Asked Questions❔

Are the manuals OEM (Original Equipment Manufacturer)?

Yes, we only provide manuals that are sourced from the machine manufacturer or authorized dealers.

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Printed versions are available for select manuals — check the product page or contact us for availability.

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Yes, all pages are printable.

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