Honda GX360 K1

Honda GX360 engineThe Honda GX360 K1 is a 359 cc (21.9 cu-in) two-cylinders, water-cooled, four-stroke cycle, internal combustion small gasoline motor with horisontal shaft, manufactured by Honda Motor Company for general-purpose applications.

The GX360 engine has an horizontal type, butterfly valve carburetor, transistorized ignition system and electric starter. It is a liquid-cooling motor with a 58 mm (2.3 in) bore and a 68 mm (2.7 in) stroke, and 8.5:1 compression ratio.

The Honda GX360 K1 develops 13.2 PS (13.0 HP, 9.7 kW) at 3,600 rpm and 25.7 Nm (2.62 kg·m; 18.97 lbf·ft) of torque at 3,000 rpm.

General information

Engine Specifications
ModelGX360 K1
Type4-stroke, OHV, 2-cylinder
Displacement359 cm 3 (21.9 cu-in)
Max. horsepower13.2 PS (13.0 HP, 9.7 kW) at 3,600 rpm
Max. torque (crank PTO)25.7 Nm (2.62 kg·m; 18.97 lbf·ft) at 3,000 rpm
CarburetorHorizontal type, butterfly valve
Cooling systemLiquid-cooling
Ignition systemTransistorized ignition
Lubricating systemForced oil by trochoid pump
Starting systemElectric starter
Stoping systemGround of primary circuit
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel tank capacity6.0 liters (6.34 US.qts, 5.28 Imp. qts)

Dimensions and Weight

Length, mm (in)515 (20.3)
Width, mm (in)490 (19.3)
Height, mm (in)530 (20.9)
Dry weight, kg (lb)45.0 (100.0)
Operating weight, kg (lb)48.5 (107.0)

Cylinder Block and Head

The GX360 featured a two main bearing crankshaft and aluminum OHV (overhead camshaft) cylinder head with 2 valves per cylinder and belt driven camshaft. The piston has two compression rings and one oil ring. Intake valves are 28 mm in diameter, and the exhaust valves are 22 mm.

Cylinder block
Compression ratio:8.5:1
Bore x Stroke58.0 X 68.0 mm (2.3 x 2.7 in)
Sleeve internal diameter58.00 mm (2.283 in)
Piston skirt outer diameter57.97 mm (2.282 in)
Number of piston rings (compression / oil):2 / 1
Piston ring side clearance (Top):0.030 mm (0.001 in)
Piston ring side clearance (Second):0.030 mm (0.001 in)
Piston ring side clearance (Oil):0.030 mm (0.001 in)
Piston ring end gap (Top):0.20 mm (0.08 in)
Piston ring end gap (Second):0.20 mm (0.08 in)
Ring width (Top):1.19 mm (0.047 in)
Ring width (Second):1.19 mm (0.047 in)
Crankshaft journal diameter33.009 mm (1.2996 in)
Crankpin diameter32.000 mm (1.2598 in)
Cylinder Head
Warpage (limit)0.10 mm (0.004 in)
Valve Arrangement:OHV
Valves:4 (2 per cylinder)
Valve head diameter (INTAKE):28.0 mm (1.10 in)
Valve head diameter (EXHAUST):22.0 mm (0.87 in)
Valve stem outer diameter (INTAKE):5.468-5.480 mm (0.2153-0.2157 in)
Valve stem outer diameter (EXHAUST):5.435-5.450 mm (0.2140-0.2146 in)
Rocker arm shaft outer diameter:12.957 mm (0.510 in)
Rocker arm internal diameter:13.015 mm (0.512 in)
Camshaft cam height (INTAKE):26.0 mm (1.024 in)
Camshaft cam height (EXHAUST):25.9 mm (1.02 in)
Camshaft outer diameter
(governor and timing side):
15.98 mm (0.629 in)

Maintenance data

Idle speed1,300 ± 150 rpm
Cylinder compression12.0 kg/cm2 (171 psi) at 500 rpm
Valve clearance
Intake valve0.10-0.14 mm (0.004-0.006 in)
Exhaust valve0.10-0.14 mm (0.004-0.006 in)
Main jet#88
Float height13.2 mm (0.52 in)
Pilot screw opening1-1/4 turns out
Oil system
Oil typeHonda 4-stroke or an equivalent (SE or SF)
Recommended oilSAE 10W-40
Oil capacity (without filter changed)1.1 liters (1.16 US.qts, 0.97 Imp. qts)
Oil capacity (with filter changed)1.4 liters (1.48 US.qts, 1.23 Imp. qts)
Oil pressure (min)2.0 kg/cm2 (28.4 psi)
Cooling system
Coolant capacity (radiator and engine)2.0 liters (2.11 US.qts, 1.76 Imp. qts)
Coolant capacity (reserve tank)0.4 liters (0.42 US.qts, 0.35 Imp. qts)
Coolant capacity (total system) 2.4 liters (2.54 US.qts, 2.11 Imp. qts)
Sub valve (start opening)77° C (171° F)
Sub valve (fully open)82° C (180° F)
Sub valve (lift height)1.5 mm (0.06 in)
Main valve (fully open)85 ° C (185 ° F)
Sub valve (lift height)6.5 mm (0.26 in)
Temperature range for continuity110° ± 2° C (230° ± 36° C)
Oil pump
Tip clearance (standard)0.15 mm (0.006 in)
Outer rotor clearance (standard)0.12-0.22 mm (0.005-0.009 in)
Rotor-to-pump body clearance (standard)0.04-0.09 mm (0.0016-0.0035 in)
Ignition system
Ignition timing24 ° ± 4 ° B.T.D.C (Fixed)
Spark plugNGK: BPR4HS
Spark plug gap0.6-0.7 mm (0.024-0.028 in)
Primary side ignition coil resistance0.9-1.1 Ω
Secondary side ignition coil resistance8.8-13.2 kΩ
Ignition coil air gap0.4 ± 0.2 (0.016 ± 0.008)
Starter motor
Brush length 14 mm (0.55 in),
Limit: 9.0 mm (0.35 in)
Mica depth (limit)0.2 mm (0.008 in)

Tightening torque specs

Tightening torque specs
Cylinder head – cylinder block (M8x1.25)22.5 Nm; 2.25 kg·m; 16.3 ft·lb
Crankcase – cylinder block (M8x1.25)22.5 Nm; 2.25 kg·m; 16.3 ft·lb
Crankcase – cylinder block (M6x1.0)10 Nm; 1.0 kg·m; 7.2 ft·lb
Connecting rod – connecting rod cup (M7x0.75)22 Nm; 2.2 kg·m; 15.9 ft·lb
Flywheel-crankshaft (M16x1.5)115 Nm; 11.5 kg·m; 83.2 ft·lb
Timing pulley – crankshaft (M30x1.0)22.5 Nm; 2.25 kg·m; 16.3 ft·lb
Crankshaft pulley – crankshaft (M10x1.25)24 Nm; 2.4 kg·m; 17 ft·lb
Crankcase cover bolt (M8x1.25)35 Nm; 3.5 kg·m; 25.3 ft·lb
Cylinder head-cover head (M6x1.0)10 Nm; 1.0 kg·m; 7 ft·lb
Timing belt cover (M6x1.0)8 Nm; 0.8 kg·m; 5.8 ft·lb
Muffler mounting nut (M8x1.25)24 Nm; 2.4 kg·m; 17 ft·lb
Exhaust manifold – cylinder head (M8x1.25)22 Nm; 2.2 kg·m; 15.9 ft·lb
Intake manifold – cylinder head (M6x1.0)10 Nm; 0.1 kg·m; 7 ft·lb
Governor arm – shaft (M6x1.0)10 Nm; 0.1 kg·m; 7 ft·lb
Water pump – cylinder block (M6x1.0)10 Nm; 1.0 kg·m; 7 ft·lb
Governor case – cylinder head (M6x1.0)10 Nm; 1.0 kg·m; 7 ft·lb
Cooling fan – shaft (M8x1.25)22.5 Nm; 2.25 kg·m; 16.3 ft·lb
Air cleaner elbow – carburetor stud (M6x1.0)8.5 Nm; 0.85 kg·m; 6.1 ft·lb
Standard torque values
Bolt, nut (5 mm)5.5 Nm; 0.55 kg·m; 4.0 ft·lb
Bolt, nut (6 mm)10 Nm; 1.0 kg·m; 7 ft·lb
Bolt, nut (8 mm)24 Nm; 2.4 kg·m; 17 ft·lb
Bolt, nut (10 mm)37.5 Nm; 3.75 kg·m; 27 ft·lb
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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  1. hi
    I have a Honda engine GX 360 K1 I Need parts list for this engine can you help me and send me the list please because I need same parts. Engine number GA01-1280846 and from were can I buy the parts?
    Thanks a lot,
    Stephan Sladden.

  2. Are there any emission factors available for this engine? Also, BSFC and/or fuel use at 100% load, and exhaust characteristics (temperature, flow rate, etc.) would be of great help. I’m trying to add this engine to a client’s air permit. Thanks.

  3. Hi i am just wondering if honda makes a 35-37 horse power water cooled motor
    That is the size of the motor that i require for the for what i have to make

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