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How to use this manual

How to use this manual

A Few Words About Safety

Service Information

The service and repair information contained in this manual is intended for use by qualified, professional technicians. Attempting

service or repairs without the proper training, tools, and equipment could cause injury to you and/or others. It could also damage

this Honda product or create an unsafe condition.
This manual describes the proper methods and procedures for performing service, maintenance, and repairs. Some procedures

require the use special tools. Any person who intends to use a replacement part, service procedure, or a tool that is not

recommended by Honda must determine the risks to their personal safety and the safe operation of this product.
If you need to replace a part, use Honda Genuine parts with the correct part number or an equivalent part. We strongly recommend

that you do not use replacement parts of inferior quality.

For Your Customer’s Safety

Proper service and maintenance are essential to the customer’s safety and the reliability of this product. Any error or oversight

while servicing this product can result in faulty operation, damage to the product, or injury to others.

For Your Safety

Because this manual is intended for the professional service technician, we do not provide warnings about many basic shop safety

practices (e.g., Hot parts-wear gloves). If you have not received shop safety training or do not feel confident about your knowledge

of safe servicing practices, we recommend that you do not attempt to perform the procedures described in this manual.
Some of the most important general service safety precautions are given below. However, we cannot warn you of every

conceivable hazard that can arise in performing service and repair procedures. Only you can decide whether or not you should

perform a given task.

Important Safety Precautions

Make sure you have a clear understanding of all basic shop safety practices and that you are wearing appropriate clothing and

using safety equipment. When performing any service task, be especially careful of the following:
 • Read all of the instructions before you begin, and make sure you have the tools, the replacement or repair parts, and the skills

required to perform the tasks safely and completely.

 • Protect your eyes by using proper safety glasses, goggles, or face shields anytime you hammer, drill, grind, or work around

pressurized air, pressurized liquids, springs or other stored-energy components. If there is any doubt, put on eye protection.

 • Use other protective wear when necessary, for example gloves or safety shoes. Handling hot or sharp parts can cause severe

burns or cuts. Before you grab something that looks like it can hurt you, stop and put on gloves.

 • Protect yourself and others whenever you have equipment hoisted in the air. Anytime you lift this product with a hoist, make sure

that the hoist hook is securely attached to the product.

Make sure the engine is off before you begin any servicing procedures, unless the instruction tells you to do otherwise. This will

help eliminate several potential hazards:
 • Carbon monoxide poisoning from engine exhaust. Be sure there is adequate ventilation whenever you run the engine.

 • Burns from hot parts. Let the engine and exhaust system cool before working in those areas.

 • Injury from moving parts. If the instruction tells you to run the engine, be sure your hands, fingers, and clothing are out of the

way.

Gasoline vapors and hydrogen gasses from batteries are explosive. To reduce the possibility of a fire or explosion, be careful when

working around gasoline or batteries.
 • Use only a nonflammable solvent, not gasoline, to clean parts.

 • Never store gasoline in an open container.

 • Keep all cigarettes, sparks, and flames away from the battery and all fuel-related parts.

Improper service or repairs can create an unsafe 

condition that can cause your customer or others to 

be seriously hurt or killed.

Follow the procedures and precautions in this 

manual and other service materials carefully.

Failure to properly follow instructions and 

precautions can cause you to be seriously hurt or 

killed.

Follow the procedures and precautions in this 

manual carefully.

Summary of Contents for GXR120RT

Page 1: ...ring appropriate clothing and using safety equipment When performing any service task be especially careful of the following Read all of the instructions before you begin and make sure you have the tools the replacement or repair parts and the skills required to perform the tasks safely and completely Protect your eyes by using proper safety glasses goggles or face shields anytime you hammer drill...

Page 2: ...INFORMATION 2 MAINTENANCE 3 TROUBLESHOOTING 4 COVER 5 FUEL SYSTEM 6 GOVERNOR SYSTEM 7 FLYWHEEL 8 IGNITION SYSTEM 9 STARTING SYSTEM 10 OTHER ELECTRICAL 11 MUFFLER 12 CAM PULLEY ROCKER ARM VALVE 13 CRANKSHAFT PISTON CYLINDER BARREL 14 WIRING DIAGRAM 15 INDEX ...

Page 3: ...ot practical or possible to warn you about all the hazards associated with servicing these products You must use your own good judgement Honda Motor Co Ltd SERVICE PUBLICATION OFFICE Date of Issue September 2013 You will find important safety information in a variety of forms including Safety Labels on the product Safety Messages preceded by a safety alert symbol and one of three signal words DANG...

Page 4: ...he hole Use only metric tools when servicing this unit Metric bolts nuts and screws are not interchangeable with non metric fasteners The use of incorrect tools and fasteners will damage the unit SYMBOLS The symbols used throughout this manual show specific service procedures If supplementary information is required pertaining to these symbols it will be explained specifically in the text without ...

Page 5: ...ne Coolant Temperature ECM Engine Control Module EMT Exhaust Manifold Temperature EOP Engine Oil Pressure EX Exhaust F Front or Forward GND Ground HO2S Heated Oxygen sensor IAB Intake Air Bypass IAC Idle Air Control IAT Intake Air Temperature I D Inside diameter IG or IGN Ignition IN Intake INJ Injection L Left MAP Manifold Absolute Pressure MIL Malfunction Indicator Lamp O D Outside Diameter OP O...

Page 6: ...ext 1 SPECIFICATIONS SERIAL NUMBER LOCATION 1 2 TYPE VARIATIONS 1 2 DIMENSIONS AND WEIGHTS SPECIFICATIONS 1 3 ENGINE SPECIFICATIONS 1 4 PERFORMANCE CURVES 1 5 DIMENSIONAL DRAWINGS 1 6 P T O DIMENSIONAL DRAWINGS 1 7 ...

Page 7: ...ght Carburetor Float Floatless Floatless with primer pump Inline fuel filter Bulge Φ5 Bulge Φ7 Air cleaner Single Dual Elbow P T O flange P T O flange A P T O flange B Engine stop switch Oil level switch Oil alert unit TYPE KRM KRB4 KRF2 KRE4 KREU KRA2 KRG KREE KRB5 KRS2 KRMB Crankshaft Tapered Straight Carburetor Float Floatless Floatless with primer pump Inline fuel filter Bulge Φ5 Bulge Φ7 Air ...

Page 8: ...RF2 KRDF KRDP KREE 294 mm 11 6 in Overall height all types 290 mm 11 4 in Dry weight KRBF KRM KRE4 KRAA KRG 10 1 kg 22 3 lbs KRB5 10 2 kg 22 5 lbs KRGA KRGF KRWF KRWB KREU 10 4 kg 22 9 lbs KRH2 10 9 kg 24 0 lbs KRH 11 0 kg 24 3 lbs KRSB KRMB KRF2 11 1 kg 24 5 lbs KRA2 KRS2 KRDY 11 2 kg 24 7 lbs KRDF KRDP KREE 11 4 kg 25 1 lbs KRB4 11 5 kg 25 4 lbs Operating weight KRBF KRM KRE4 KRAA KRG 10 3 kg 22...

Page 9: ...Net power SAE J1349 1 2 7 kW 3 6 HP 3 600 min 1 rpm Continuous rated power 2 1 kW 2 8 HP 3 600 min 1 rpm Maximum net torque SAE J1349 1 7 5 N m 0 8 kgf m 5 5 lbf ft 2 500 min 1 rpm Compression ratio 8 5 1 Fuel consumption at continuous rated power 1 0 Liter 0 26 US gal 0 22 Imp gal h Ignition system Transistorized magneto ignition Ignition timing 25 B T D C Recommended spark plug CR5HSB NGK U16FSR...

Page 10: ...ICATIONS PERFORMANCE CURVES lbf ft kgf m N m 8 kW 2 1 0 3 TORQUE OUTPUT HP PS 5 5 0 5 4 3 2 1 0 3 2 1 0 NET POWER NET TORQUE RECOMMENDED OPERATING SPEED RANGE 2000 3000 3600 ENGINE SPEED rpm 4 7 6 5 5 0 4 5 4 0 0 6 0 8 2500 4000 0 7 ...

Page 11: ...U KRH KRSB KRMB KRF2 KRDF KRDP KREE E type KRGA KRGF KRWF KRWB KREU KRBF KRAA KRG KRB5 F type KRDF KRDP KREE KRM KRE4 KRB4 KRDY G type KRH KRH2 KRSB KRMB KRF2 KRA2 KRS2 123 4 8 M8 x 1 25 4 PLACES DEPTH16 94 3 7 290 11 4 154 6 1 A type 264 10 4 B type 268 10 6 C type 283 11 1 D type 294 11 6 A type 141 5 6 B type 145 5 7 C type 160 6 3 D type 171 6 7 E type 259 10 2 F type 271 10 7 G type 273 10 7 ...

Page 12: ...1 25 117 5 4 63 From cylinder center 51 3 2 02 34 2 1 35 78 3 1 51 3 2 02 94 3 7 51 3 2 02 17 0 7 18 0 7 15 0 59 M8 x 1 25 Φ11 5 PLACES Φ17 M10 x 1 25 2 PLACES TAPER 1 5 4 00 4 03 0 157 0 159 11 388 11 497 0 4483 0 4526 15 0 59 Φ11 5 PLACES M10 x 1 25 2 PLACES 117 5 4 63 From cylinder center M12 x 1 25 14 976 14 994 0 5896 0 5903 Φ21 9 6 3 78 ...

Page 13: ...6 3 8 M8 x 1 25 114 5 4 51 From cylinder center 18 0 7 23 7 0 93 17 0 7 17 000 17 003 Φ9 5 4 PLACES TAPER 1 5 CRANKSHAFT P T O 4 00 4 03 0 157 0 159 11 388 11 497 0 4483 0 4526 14 976 14 994 0 5896 0 5903 Φ21 M12 x 1 25 114 5 4 51 From cylinder center Φ9 5 4 PLACES 9 6 3 78 ...

Page 14: ...2 1 2 dummytext 2 SERVICE INFORMATION MAINTENANCE STANDARDS 2 2 TORQUE VALUES 2 3 LUBRICATION SEAL POINTS 2 4 TOOLS 2 5 HARNESS AND TUBE ROUTING 2 6 ...

Page 15: ...354 Big end oil clearance 0 040 0 063 0 0016 0 0025 0 12 0 0047 Crankshaft Crankpin O D 25 970 25 980 1 0224 1 0228 25 920 1 0205 Crankshaft runout 0 10 0 004 in Valves Valve clearance IN 0 15 0 04 0 006 0 002 EX 0 20 0 04 0 008 0 002 Valve stem O D IN 3 970 3 985 0 1563 0 1569 3 900 0 1535 EX 3 935 3 950 0 1549 0 1555 3 880 0 1528 Valve guide Valve guide I D IN EX 4 000 4 018 0 1575 0 1582 4 060 ...

Page 16: ...age 7 2 Stopper plate screw M3 x 0 5 1 0 1 0 7 Breather pipe bolt M4 x 0 7 3 5 0 36 2 6 Air cleaner stud bolt M6 x 1 0 12 1 2 9 Air cleaner case nut 5 mm M5 x 0 8 5 5 0 60 4 1 Air cleaner case nut 6 mm M6 x 1 0 8 5 0 87 6 3 Air cleaner cover bolt M6 x 1 0 2 3 0 23 1 7 Muffler nut M6 x 1 0 12 1 2 9 Item Tread Dia mm Torque values N m kgf m lbf ft Screw 5 mm 4 3 0 4 3 2 6 mm 9 0 9 6 6 Bolt and nut 5...

Page 17: ...m seal lips Valve spring entire surface Valve adjusting screw threads Valve adjusting lock nut threads and seating surface Rocker arm pivot and slipper surface Rocker arm shaft entire surface Timing belt entire surface Flywheel nut threads and seating surface Governor weight holder gear Governor holder shaft journal Governor arm shaft journal Each oil seal outer surface Multi purpose grease Each O...

Page 18: ...mm 07908 KE90200 Cleaning brush 07998 VA20100 Valve guide driver 3 6 x 8 0 mm 07JMD KY20100 Valve guide reamer 4 008 mm 07MMH MV90100 Driver 07749 0010000 Driver 22 mm I D 07746 0020100 Attachment 44 x 49 5 mm 07945 3330300 Attachment 32 x 35 mm 07746 0010100 Attachment 37 x 40 mm 07746 0010200 Pilot 22 mm 07746 0041000 ...

Page 19: ...LESS TYPE ENGINE STOP SWITCH ENGINE STOP SWITCH ENGINE STOP SWITCH CORD HIGH TENSION CORD HIGH TENSION CORD With OIL LEVEL SWITCH AND OIL ALERT UNIT TYPE Without OIL LEVEL SWITCH AND OIL ALERT UNIT TYPE ENGINE STOP SWITCH CORD HIGH TENSION CORD ENGINE STOP SWITCH CORD to OIL ALERT UNIT ENGINE STOP SWITCH CORD to OIL ALERT UNIT ENGINE STOP SWITCH CORD ENGINE STOP SWITCH CORD to OIL ALERT UNIT ENGIN...

Page 20: ...NFORMATION OIL LEVEL SWITCH CORD OIL LEVEL SWITCH PLUG ENGINE STOP CORD OIL ALERT UNIT PLUG OIL ALERT UNIT CORD OIL LEVEL SWITCH CORD Y Y Bl Bl Bu to IGNITION COIL to OIL LEVEL SWITCH OIL ALERT UNIT OIL LEVEL SWITCH CORD 0 20 10 15 mm ...

Page 21: ...8 dummyhead dummyhead SERVICE INFORMATION AIR VENT TUBE DRAIN TUBE FUEL TUBE FUEL TUBE FUEL FILTER FUEL TUBE 1 0 2 0 mm 0 04 0 08 30 RETURN TUBE FUEL TUBE FUEL FILTER FUEL TUBE 1 0 2 0 mm 0 04 0 08 30 30 ...

Page 22: ...2 9 dummyhead dummyhead SERVICE INFORMATION AIR VENT TUBE DRAIN TUBE FUEL TUBE FUEL TUBE AIR VENT TUBE 1 0 2 0 mm 0 04 0 08 30 ...

Page 23: ...MEMO dummyhead dummyhead ...

Page 24: ...3 2 ENGINE OIL LEVEL CHECK CHANGE 3 3 AIR CLEANER CHECK CLEANING REPLACEMENT 3 4 SPARK PLUG CHECK ADJUSTMENT 3 5 SPARK PLUG REPLACEMENT 3 5 TIMING BELT CHECK 3 6 IDLE SPEED CHECK ADJUSTMENT 3 6 COMBUSTION CHAMBER CLEANING 3 7 VALVE CLEARANCE CHECK ADJUSTMENT 3 7 ...

Page 25: ...aning brush 07998 VA20100 ITEM Perform at every indicated month or operating hour interval whichever comes first REGULAR SERVICE PERIOD 1 Refer to page Each use First month or 20 hrs Every 3months or 50 hrs Every 6 months or 100 hrs Every year or 200 hrs Engine oil Check level 3 3 Change 3 3 Air cleaner Check 3 4 Clean 2 3 4 Replace 2 3 4 Spark plug Check adjust 3 5 Replace 3 5 Timing belt Check A...

Page 26: ...he trash pour it on the ground or pour it down a drain Install the drain plug bolt with a new drain plug washer and tighten it to the specified torque Add the specified amount of recommended oil into the engine After adding the engine oil check the oil level Check that the oil filler cap packing 4 is in good condition replace it if necessary Install and tighten the oil filler cap securely Make sur...

Page 27: ...s for holes or tears and replace if damaged Clean both air cleaner elements if they are to be reused page 3 4 Installation is in the reverse order of removal ELEMENT CLEANING FOAM Clean the filter 1 in warm soapy water rinse and allow to dry thoroughly or clean with a non flammable solvent and allow to dry thoroughly Dip the filter in clean engine oil and squeeze out all the excess oil Excess oil ...

Page 28: ...t the spark plug cap 1 and remove the spark plug 2 Clean around the spark plug base with compressed air before removing the spark plug and be sure that no debris is allowed to enter into the combustion chamber INSTALLATION Install and hand tighten the spark plug to the cylinder head Tighten the spark plug to the specified torque Connect the spark plug cap RECOMMENDED SPARK PLUG CR5HSB NGK U16FSR U...

Page 29: ...ECK ADJUSTMENT Use a tachometer with graduations of 50 min 1 rpm or smaller that will accurately indicate a 50 min 1 rpm change Start the engine and allow it to warm up to normal operating temperature With the engine idling turn the throttle stop screw 1 to obtain the standard idle speed 1 IDLE SPEED 1 850 150 min 1 rpm 1 FLOAT TYPE FLOATLESS TYPE 1 ...

Page 30: ...s the cleaning brush with force against the combustion chamber VALVE CLEARANCE CHECK ADJUSTMENT Inspect and adjust the valve clearance while the engine is cold CHECK Remove the following Recoil starter page 10 2 Head cover page 13 4 Set the piston to top dead center of the compression stroke both valves fully closed Top dead center of the compression stroke is the point where the cutout 1 in the s...

Page 31: ...turning the adjusting screw until there is a slight drag on the feeler gauge Hold the valve adjust screw using the special tool and retighten the lock nut to the specified torque Recheck the valve clearance and if necessary readjust the clearance Install the following Head cover page 13 4 Recoil starter page 10 2 VALVE CLEARANCE IN 0 15 0 04 mm 0 006 0 002 in EX 0 20 0 04 mm 0 008 0 002 in 3 1 2 T...

Page 32: ...4 1 4 dummytext 4 TROUBLESHOOTING BEFORE TROUBLESHOOTING 4 2 TROUBLESHOOTING 4 2 ...

Page 33: ...Check the cylinder compression page 13 9 Check the valve clearance page 3 8 and then perform the cylinder compression test If the cylinder compression is too high remove carbon deposits in the combustion chamber page 3 8 Check the decompressor operation of the camshaft page 13 6 Check the valve clearance page 3 8 and then perform the cylinder compression test If the cylinder compression is too low...

Page 34: ...n the carburetor page 6 6 6 8 Inspect the spark plug and adjust the spark plug gap Replace if necessary page 3 6 Adjust the valve clearance page 3 9 Clear Normal No air leaking Clean Adjust the ignition coil air gap page 9 4 Abnormal Adjust or replace the faulty part s Abnormal Normal Check the air cleaner element page 3 5 Check the spark plug page 3 6 Check the valve clearance page 3 8 Check the ...

Page 35: ...s are found and recheck Abnormal Normal Continuity No continuity Replace the engine stop switch page 11 3 Check the engine stop switch page 11 4 Check the wire harness connecting the oil level switch and ignition coil for open or short circuit Replace the engine wire harness No continuity Abnormal Replace the oil level switch page 11 3 Normal Continuity Check the oil level switch page 11 5 Check t...

Page 36: ...15 1 15 dummytext 15 WIRING DIAGRAM HOW TO READ A WIRING DIAGRAM RELATED INFORMATION 15 2 WIRING DIAGRAMS 15 4 ...

Page 37: ...e shown for the dedicated connectors The double frame connectors represent the male connectors and the single frame connectors represent the female connectors Both the male and female connectors are shown by viewing them from the terminal side TERMINAL No The system drawing shows the No 9 terminal of the connector FEMALE CONNECTOR MALE CONNECTOR VIEWING DIRECTION VIEWING DIRECTION FEMALE CONNECTOR...

Page 38: ... Lg Light green R Red P Pink W White Gr Gray SYMBOL OF TERMINAL It shows the shape of each terminal to identify whether it is a male or female terminal TERMINAL No CONNECTOR TERMINAL No Every connector and terminal has a number to help the users find the location and shape of the connector and the terminal arrangement by referring to the Connector general layout drawing and or the Connector drawin...

Page 39: ...P SWITCH TYPE OIL LEVEL SWITCH AND OIL ALERT UNIT TYPE ENGINE STOP SWITCH UNIT IGNITION COIL SPARK PLUG Bl Bl Bl Black ENGINE STOP SWITCH UNIT IGNITION COIL SPARK PLUG LED Bl Bl Bl Gr Y Y OIL LEVEL SWITCH OIL ALERT UNIT Bu OEM PARTS Bl Black Bu Blue Gr Green Y Yellow ...

Page 40: ...H HARNESS AND TUBE ROUTING 2 6 HOW TO READ A WIRING DIAGRAM RELATED INFORMATION 15 2 I IDLE SPEED CHECK ADJUSTMENT 3 6 IGNITION COIL AIR GAP CHECK ADJUSTMENT 9 4 IGNITION COIL INSPECTION 9 5 IGNITION COIL REMOVAL INSTALLATION 9 3 IGNITION SYSTEM TROUBLESHOOTING 9 2 L LUBRICATION SEAL POINTS 2 4 M MAINTENANCE SCHEDULE 3 2 MAINTENANCE STANDARDS 2 2 METERING LEVER ADJUSTMENT FLOATLESS TYPE 6 8 MUFFLE...

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