Subaru-Robin EX35D

Subaru-Robin EX35DThe Subaru-Robin EX35D is a 404 cc (24.65 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 EX35D 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.

An 89.0 mm (3.5 in) cylinder bore and 65.0 mm (2.56 in) piston stroke give the motor a total 404 cc (24.65 cu-in) of displacement. Compression ratio rating is 8.3:1. The engine produced 12.0 PS (8.8 kW; 11.8 HP) at 3,600 rpm of maximum horsepower and 7.5 PS (5.5 kW; 7.4 HP) at 3,000 rpm or 8.6 PS (6.3 kW; 8.4 HP) at 3,600 rpm of continuous output power. Maximum torque is 26.0 N·m (2.7 kg·m, 19.2 ft·lb) at 2,400 rpm.

General information

Engine Specifications
Model EX35D
Type 4-stroke, OHC, single cylinder
Displacement 404 cm 3 (24.65 cu-in)
Max. horsepower 12.0 PS (8.8 kW; 11.8 HP) at 3,600 rpm
Max. torque (crank PTO) 26.0 N·m (2.7 kg·m, 19.2 ft·lb) at 2,400 rpm
Carburetor Horizontal draft, float type carburetor
Cooling system Forced-air
Ignition system Transistorized magneto ignition
Lubricating system Splash
Starting system Recoil or electric starter
Stoping system Ignition primary circuit ground
Fuel used Unleaded gasoline (octane number 86 or higher)
Fuel tank capacity 7.0 L (1.85 US. gal. 1.54 Imp. gal.)
PTO shaft rotation Counterclockwise (from PTO shaft side)

Cylinder Block and Head

The EX35D 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 Stroke 89.0 mm x 65.0 mm (3.5 x 2.56 in)
Sleeve internal diameter 89.000-89.022 mm (3.5039-3.5048 in)
Piston skirt outer diameter 88.980-89.000 mm (3.5031-3.5039 in)
Number of piston rings (compression / oil): 1 / 1
Ring side clearance Top 0.050-0.080 mm (0.002-0.0031 in)
Oil 0.030-0.125 mm (0.0012-0.0049 in)
Ring end gap Top 0.10-0.25 mm (0.0039-0.0098 in)
Oil 0.15-0.55 mm (0.0059-0.0217 in)
Connecting rod small end ID 21.010-21.023 mm (0.8272-0.8277 in)
Connecting rod big end ID 38.000-38.016 mm (1.4961-1.4967 in)
Piston pin outer diameter 20.992-21.000 mm (0.8265-0.8268 in)
Crankshaft crankpin outer diameter 37.956-37.970 mm (1.4943-1.4949 in)
Crankshaft main journal diameter 34.986-34.997 mm (1.3774-1.3778 in)/td>
Cylinder Head
Warpage (limit) 0.10 mm (0.004 in)
Valve Arrangement: OHC
Valves: 2
Stem outer diameter (standard): INTAKE 5.970-5.985 mm (0.235-0.2356 in)
EXHAUST 5.970-5.985 mm (0.235-0.2356 in)
Valve spring free length: 36.5 mm (1.437 in)
Camshaft lobe height: INTAKE 35.658-35.758 mm (1.4039-1.4078 in)
EXHAUST 39.408-39.508 mm (1.5515-1.5554 in)

Tightening torque specs

Tightening torque specs
Cylinder head M10 × 75 flange bolt (Re-use) 29-31 Nm; 2.9-3.1 kg·m; 21.0-22.4 ft·lb
Cylinder head M10 × 75 flange bolt (New) 37-39 Nm; 3.7-3.9 kg·m; 26.7-28.2 ft·lb
Cylinder head M8 × 35 flange bolt 17-19 Nm; 1.7-1.9 kg·m; 12.3-13.7 ft·lb
Connecting rod bolt 22-27 Nm; 2.2-2.7 kg·m; 16.3-19.9 ft·lb
Main bearing cover bolts 22-24 Nm; 2.2-2.4 kg·m; 16.2-17.7 ft·lb
Flywheel nut 100-120 Nm; 10.0-12.0 kg·m; 72.3-86.8 ft·lb

Service Information

Cylinder compression 4.5 kg/cm2
Valve clearance
Intake valve clearance 0.12-0.15 mm (0.0047-0.0059 in)
Exhaust valve clearance 0.12-0.15 mm (0.0047-0.0059 in)
Oil system
Oil type 4-stroke or an equivalent (SE or SF)
Recommended oil SAE 10W-30
Oil capacity 1.2 L (1.27 US. qt, 1.06 Imp. qt.)
Fuel system
Type: Horizontal draft, float type carburetor
Main jet: URETHANE: 109, DUAL: 107
Slow jet: URETHANE: 40, DUAL: 44
Ignition system
Spark plug NGK: BR-6HS;
Spark plug gap 0.6-0.7 mm (0.0236-0.0276 in)
Spark plug torque: 25 N·m (2.5 kg·m, 18.4 ft·lb)
Ignition coil air gap 0.3-0.5 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.

ATTENTION! Dear visitors, this site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.

Be the first to comment

Leave a Reply

Your email address will not be published.