Subaru-Robin EX30D

Subaru-Robin EX30DThe Subaru-Robin EX30D is a 287 cc (17.51 cu·in) single-cylinder air-cooled 4-stroke internal combustion small gasoline engine manufactured by Industrial Products division of Subaru Corporation for general-purpose applications.

The Subaru-Robin EX30D engine has an OHС (overhead camshaft) design; high compression ratio for better fuel efficiency; horizontal draft, float type carburetor; recoil starter or electric starter as option and transistorized magneto ignition system.

A 75.0 mm (2.95 in) cylinder bore and 65.0 mm (2.56 in) piston stroke give the motor a total 265 cc (16.17 cu-in) of displacement. The engine produced 9.0 PS (6.6 kW; 8.9 HP) at 4,000 rpm of maximum horsepower.

General information

Engine Specifications
Type4-stroke, OHC, single cylinder
Displacement287 cm 3 (17.51 cu-in)
Max. horsepower9.0 PS (6.6 kW; 8.9 HP) at 4,000 rpm
Max. torque (crank PTO)
CarburetorHorizontal draft, float type carburetor
Cooling systemForced-air
Ignition systemTransistorized magneto ignition
Lubricating systemSplash
Starting systemRecoil or electric starter
Stoping systemIgnition primary circuit ground
Fuel usedUnleaded gasoline (octane number 86 or higher)
PTO shaft rotationCounterclockwise (from PTO shaft side)

Cylinder Block and Head

The EX30D has cast iron cylinder sleeve, ball bearing supported forged steel crankshaft, improved piston design. The piston has single compression rings and a single oil ring.

Cylinder block
Bore x Stroke75.0 x 65.0 mm (2.95 x 2.56 in)
Sleeve internal diameter75.000-75.019 mm (2.9528-2.9535 in)
Piston skirt outer diameter74.980-75.000 mm (2.952-2.9528 in)
Number of piston rings (compression / oil):1 / 1
Ring side clearanceTop0.035-0.080 mm (0.0014-0.0031 in))
Oil0.0100-0.205 mm (0.0004-0.0081 in)
Ring end gapTop0.10-0.30 mm (0.0039-0.0118 in)
Oil0.20-0.70 mm (0.0079-0.0276 in)
Connecting rod small end ID18.010-18.020 mm (0.7091-0.7094 in)
Connecting rod big end ID34.500-34.516 mm (1.3583-1.3589 in)
Piston pin outer diameter17.992-18.000 mm (0.7083-0.7087 in)
Crankshaft crankpin outer diameter34.467-34.480 mm (1.357-1.3575 in)
Crankshaft main journal diameter29.998-29.997 mm (1.181-1.181 in)
Cylinder Head
Warpage (limit)0.10 mm (0.004 in)
Valve Arrangement:OHC
Stem outer diameter (standard):INTAKE5.440-5.455 mm (0.2142-0.2148 in)
EXHAUST5.425-5.445 mm (0.2136-0.2144 in)
Valve spring free length:27.4 mm (1.0787 in)
Camshaft lobe height:INTAKE29.431-29.531 mm (1.1587-1.1626 in)
EXHAUST29.431-29.531 mm (1.1587-1.1626 in)

Tightening torque specs

Tightening torque specs
Cylinder head M8 × 68 flange bolt (Re-use)25-27 Nm; 2.5-2.7 kg·m; 18.1-19.5 ft·lb
Cylinder head M8 × 68 flange bolt (New)28-30 Nm; 2.8-3.0 kg·m; 20.3-21.7 ft·lb
Cylinder head M8 × 35 flange bolt17-19 Nm; 1.7-1.9 kg·m; 12.3-13.7 ft·lb
Connecting rod bolt17-20 Nm; 1.7-2.0 kg·m; 12.3-14.5 ft·lb
Main bearing cover bolts22-24 Nm; 2.2-2.4 kg·m; 16.2-17.7 ft·lb
Flywheel nut59-64 Nm; 5.9-6.4 kg·m; 42.7-46.3 ft·lb

Service Information

Cylinder compression5.0 kg/cm2
Valve clearance
Intake valve clearance0.11-0.16 mm (0.0043-0.0063 in)
Exhaust valve clearance0.11-0.16 mm (0.0043-0.0063 in)
Oil system
Oil type4-stroke or an equivalent (SE or SF)
Recommended oilSAE 10W-30
Oil capacity1.0 L (1.06 US. qt, 0.88 Imp. qt.)
Fuel system
Type:Horizontal draft, float type carburetor
Main jet:#98
Pilot screw opening:1-1/2 turns out
Ignition system
Spark plug NGK: BR-6HS;
Spark plug gap0.6-0.7 mm (0.0236-0.0276 in)
Spark plug torque:25 N·m (2.5 kg·m, 18.4 ft·lb)
Ignition coil air gap0.3-0.5 mm (0.0118-0.0118 in)
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. Good afternoon, a lot of oil is coming out of the gas outlet of the valve cover and it comes out of the air filter, which must be happening, thank you for any help you can provide.

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