Honda GX240 T2/U2/UT2

Honda GX240 engineThe Honda GX240 R2/RT2/T2/U2/UT2 is a 270 cc (16.5 cu·in) single-cylinder, air-cooled, four-stroke cycle, internal combustion small gasoline engine with horizontal shaft, manufactured by Honda Motor Company for general-purpose applications, such as: pressure washers, commercial lawn and garden equipment, tillers and cultivators, generators, construction or industrial equipment, agricultural equipment, small vehicles and water pumps.

This engine has an OHV design for increased efficiency and optimal power transfer; digital CDI (Capacitor Discharge Ignition) ignition system with variable timing; sophisticated air intake system; large capacity, multi-chamber exhaust system; heavy-duty recoil starter.

The GX240 R2/RT2/T2/U2/UT2 has few differences from GX240 UT1/T1/U1/K1: larger displacement 270 cc (GX240 K1 has 242 cc), larger piston diameter 77.0 mm (GX240 K1 has 73.0 mm), a compression ratio is increased to 8.5:1 (GX240 K1 – 8.2:1). This engine is equipped digital CDI ignition system (GX240 K1 has transistorized magneto ignition).

The second-generation Honda GX240 engine produces 8.01 PS (7.9 HP, 5.9 kW) at 3,600 rpm of max. output power and 18.3 Nm (1.86 kg·m, 13.4 lbf·ft) at 2,500 rpm of peak torque .

PTO Shaft Options

  • E type – tapered shaft;
  • H type – 1/6 reduction type PTO;
  • L type – 1/2 reduction type PTO;
  • P type – threaded type (SAE);
  • Q type – straight shaft;
  • R type – 1/2 reduction type PTO with centrifugal clutch;
  • V type – tapered shaft;

General information

Engine Specifications
ModelGX240 R2/RT2/T2/U2/UT2
Description codeR2 (GCBPK), RT2 (GCBJT), T2 (GCBKT), U2 (GCBPK), UT2 (GCBJT)
Type4-stroke, OVH, single cylinder, inclined by 25°
Displacement270 cm 3 (16.5 cu·in)
Max. horsepower8.01 PS (7.9 HP, 5.9 kW) at 3,600 rpm
Max. torque (crank PTO)18.3 Nm (1.86 kg·m, 13.4 lbf·ft) at 2,500 rpm
CarburetorHorizontal type, butterfly valve
Cooling systemForced-air
Ignition systemC.D.I.(Capacitor Discharge Ignition) type magneto ignition
Lubricating systemForced splash
Starting systemRecoil, Recoil and Starter motor
Stoping systemIgnition exciter coil circuit open
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel consumption2.2 Liters (0.58 US gal, 0.48 Imp gal) / h
PTO shaft rotationCounterclockwise (from PTO shaft side)

Dimensions and Weight

GX240 UT2
Type SType QType LType RType HType WType PType V
Length, mm (in)355 (14.0)380 (15.0)405 (15.9)440 (17.3)425 (16.7)370 (14.6)380 (15.0)400 (15.7)
Width, mm (in)428 (16.9)
Height, mm (in)422 (16.6)
Dry weight, kg (lb)25.8 (56.9)25.8 (56.9)26.5 (58.4)30 (66.1)26.5 (58.4)25.8 (56.9)25.8 (56.9)25.8 (56.9)
weight, kg (lb)
30.5 (67.2)30.5 (67.2)31.5 (69.4)35 (77.2)31.5 (69.4)30.5 (67.2)30.5 (67.2)30.5 (67.2)
GX240 R2GX240 RT2GX240 T2GX240 U2
Type EType VType HType PType QType L
Length, mm (in)360 (14.2)420 (16.5)425 (16.7)380 (15.0)380 (15.0)405 (15.9)
Width, mm (in)428 (16.9)
Height, mm (in)303 (11.9)303 (11.9)410 (16.1)410 (16.1)410 (16.1)422 (16.6)
Dry weight, kg (lb)21.4 (47.2)21.4 (47.2)26.5 (58.4)25.8 (56.9)25.8 (56.9)26.5 (58.4)
weight, kg (lb)
26.1 (57.5)26.1 (57.5)31.5 (69.4)30.5 (67.2)30.5 (67.2)31.5 (69.4)

Cylinder Block and Head

The Honda GX240 engine has a cast iron cylinder sleeve, ball bearing supported crankshaft, improved piston design, heavy duty balancer shaft. The piston has two compression rings and one oil ring. Precision camshaft design offers precise valve timing and optimal valve overlap for better fuel efficiency. The compression ratio rating is 8.5:1.

Cylinder block
Compression ratio:8.5:1
Bore x Stroke77.0 X 58.0 mm (3.0 x 2.3 in)
Sleeve internal diameter77.000-77.017 mm (3.0315-3.0322 in)
Piston skirt outer diameter76.975-76.985 mm (3.0305-3.0309 in)
Number of piston rings (compression / oil):2 / 1
Piston ring side clearance (Top):0.030-0.060 mm (0.0012-0.0024 in)
Piston ring side clearance (Second):0.030-0.060 mm (0.0012-0.0024 in)
Piston ring side clearance (Oil):0.030-0.060 mm (0.0012-0.0024 in)
Piston ring end gap (Top):0.200-0.350 mm (0.0079-0.0138 in)
Piston ring end gap (Second):0.350-0.500 mm (0.0138-0.0197 in)
Piston ring end gap (Oil – side rail):0.200-0.700 mm (0.010-0.030 in)
Ring width (Top):1.160-1.175 mm (0.0457-0.0463 in)
Ring width (Second):1.160-1.175 mm (0.0457-0.0463 in)
Piston pin outer diameter17.994-18.000 mm (0.7084-0.7087 in)
Piston pin bore inner diameter18.002-18.008 mm (0.7087-0.7090 in)
Conrod small end inner diameter18.005-18.020 mm (0.7089-0.7094 in)
Conrod big end inner diameter33.025-33.039 mm (1.3002-1.3007 in)
Crankshaft outer diameter32.975-32.985 mm (1.2982-1.2986 in)
Cylinder Head
Warpage (limit)0.10 mm (0.004 in)
Valve Arrangement:OHV
Valve stem outer diameter (INTAKE):6.575-6.590 mm (0.2589-0.2594 in)
Valve stem outer diameter (EXHAUST):6.535-6.550 mm (0.2573-0.2579 in)
Valve guide inner diameter (INTAKE):6.600-6.615 mm (0.2598-0.2604 in)
Valve guide inner diameter (EXHAUST):6.600-6.615 mm (0.2598-0.2604 in)
Guide-to-stem clearance (INTAKE):0.010-0.040 mm (0.0004-0.0016 in)
Guide-to-stem clearance (EXHAUST):0.050-0.080 mm (0.002-0.0031 in)
Camshaft cam height (INTAKE):31.945-32.145 mm (1.2577-1.2655 in)
Camshaft cam height (EXHAUST):31.666-31.866 mm (1.2467-1.2546 in)
Valve seat width:1.0-1.2 mm (0.040-0.050 in)
Valve spring free length:39.0 mm (1.54 in)
Camshaft outer diameter:15.966-15.984 mm (0.6286-0.6293 in)

Maintenance data

Maximum speed3,850 ± 150 rpm
Idle speed1,400 ± 150 rpm
Cylinder compression6.0-8.5 kg/cm2 (85-121 psi, 0.59 – 0.83 MPa) at 600 rpm
Valve clearance
Intake valve0.15 ± 0.02 mm (0.006 ± 0.001 in)
Exhaust valve0.20 ± 0.02 mm (0.008 ± 0.001 in)
Main jetBE70R A: #85
BE71F A: #85
Float height13.2 mm (0.52 in)
Pilot screw opening1 turns out
Oil system
Oil typeHonda 4-stroke or an equivalent (SE or later)
Recommended oilSAE 10W-30
Oil capacity1.1 liters (1.16 US.qts, 0.97 Imp. qts)
Ignition system
Ignition timingB.T.D.C. 10° / 1,400 rpm
Spark plugNGK: BPR6ES
Spark plug gap0.7-0.8 mm (0.028-0.031 in)
Ignition coil air gap0.2-0.6 mm (0.01-0.02 in)
Starter motor
Brush length 7.0 mm (0.28 in)
Limit: 3.5 mm (0.14 in)
Mica depth 1.0 mm (0.04 in)
Limit: 0.2 (0.01)

Tightening torque specs

Tightening torque specs
Connecting rod bolt (M8x1.25 Special)14 Nm; 1.4 kg·m; 10 ft·lb
Cylinder head bolt (M10x1.25)35 Nm; 3.5 kg·m; 25 ft·lb
Flywheel nut (M16x1.5 Special)115 Nm; 11.5 kg·m; 83 ft·lb
Rocker arm pivot lock nut (M6x0.5)10 Nm; 1.0 kg·m; 7 ft·lb
Rocker arm pivot bolt (M8x1.25 Special)24 Nm; 2.4 kg·m; 17 ft·lb
Crankcase cover bolt (M8x1.25)24 Nm; 2.4 kg·m; 17 ft·lb
Oil level switch joint nut (M10x1.25)10 Nm; 1.0 kg·m; 7 ft·lb
Fuel filter joint nut (M10x1.25)2 Nm; 0.2 kg·m; 1.4 ft·lb
Muffler mounting nut (M8x1.25)24 Nm; 2.4 kg·m; 17 ft·lb
Air cleaner wing nut (M6x1.0)9 Nm; 0.9 kg·m; 6.5 ft·lb
Oil drain bolt (M12x1.5)23 Nm; 2.3 kg·m; 17 ft·lb
Fuel tank bolt (M8x1.25)24 Nm; 2.4 kg·m; 17 ft·lb
Air cleaner mounting nut (M6x1.0)10 Nm; 1.0 kg·m; 7 ft·lb
Fuel strainer cup (M24x1.0)4 Nm; 0.4 kg·m; 2.9 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
Bolt, nut (12 mm)55 Nm; 5.5 kg·m; 40 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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