The Kubota D1305 is a 1.3 L (1,261 cc, 76.95 cu·in) natural aspirated three-cylinders four-stroke liquid-cooled internal combustion small diesel engine, manufactured by Kubota for general-purpose applications.
A 78.0 mm (3.07 in) cylinder bore and 88.0 mm (3.46 in) piston stroke give the D1305 engine a total of 1,261 cc of displacement. The compression ratio rating is 24.0:1.
The Kubota D1305 diesel engine produces 28.6 PS (21.0 KW; 28.2 HP) at 3,000 rpm of net output power and 29.5 PS (21.7 KW; 29.1 HP) at 3,000 rpm of gross horsepower. The D1305-E4B engine produces 24.3 PS (17.9 KW; 24.0 HP) at 2,600 rpm of net horsepower and 25.2 PS (18.5 KW; 24.8 HP) at 2,600 rpm of gross horsepower.
The Kubota D1305 features:
- Spherical type (E-TVCS) combustion chamber
- Bosch MD type mini fuel injection pump
- Mini nozzle (DNOPD) injection nozzle
- All speed mechanical governor
- Forced lubrication by trochoid pump lubrication system
- Liquid-cooled cooling system
- Electric starting with 12V starter
General information
| Engine Specifications | |
| Engine model | D1305-E3B, D1305-E4B |
| Engine type | 4-stroke, vertical, three-cylinders |
| Displacement | 1.3 L, 1,261 cm3, (76.95 cu·in) |
| Max. horsepower | D1305-E3B Net: 28.6 PS (21.0 KW; 28.2 HP) at 3,000 rpm Gross: 29.5 PS (21.7 KW; 29.1 HP) at 3,000 rpm D1305-E4B Net: 24.3 PS (17.9 KW; 24.0 HP) at 2,600 rpm Gross: 25.2 PS (18.5 KW; 24.8 HP) at 2,600 rpm |
| Max. torque | – |
| Cooling system | Liquid-cooled |
| Lubricating system | Forced lubrication by trochoid pump |
| Fuel injection pump | Bosch MD type mini fuel injection pump |
| Fuel nozzle | Mini nozzle (DNOPD) |
| Fuel used | Diesel fuel No. 2-D |
| Firing order | 1-2-3 |
| Starting system | Electric starter (12V, 1.1kW or 1.2kW) |
| Starting support device | Glow plug in combustion chamber |
| Governor | All speed mechanical governor |
| Charging system | Alternator 12V |
| PTO shaft rotation | Counterclockwise |
| Dimensions (L x W X H) | 498 x 397 x 590 mm (19.6 x 15.6 x 23.0 in) |
| Dry weight | 95 kg (210 lbs) |
Cylinder Block and Head
| Cylinder block | |
| Compression ratio: | 24.0:1 |
| Cylinder bore: | 78.0 mm (3.07 in) |
| Piston stroke: | 78.4 mm (3.09 in) |
| Cylinder internal diameter (standard): | 78.00-78.019 mm (3.0709-3.0716 in) |
| Number of piston rings (compression / oil): | 2/1 |
| Connecting rod small end diameter (standard): | 22.025-22.040 mm (0.8671-0.8677 in) |
| Piston pin diameter: | 22.002-22.011 mm (0.8662-0.8666 in) |
| Side clearance (Second): | 0.085-0.112 mm (0.0033-0.0044 in) |
| Side clearance (Oil): | 0.020-0.055 mm (0.0008-0.0022 in) |
| Ring end gap (Top): | 0.200-0.350 mm (0.0079-0.0130 in) |
| Ring end gap (Second): | 0.300-0.450 mm (0.0118-0.0177 in) |
| Ring end gap (Oil): | 0.300-0.550 mm (0.0120-0.0210 in) |
| Crankshaft main journal diameter: | 51.921-51.940 mm (2.0442-2.0448 in) |
| Crankpin journal diameter: | 39.959-39.975 mm (1.5732-1.5738 in) |
| Crankshaft center distance: | 36.8 mm (1.45 in) |
| Cylinder head | |
| Valve arrangement: | OHV, gear drive |
| Valves: | 2 (6 valves in total) |
| Valve head diameter (INTAKE): | 33.0 mm (1.3 in) |
| Valve head diameter (EXHAUST): | 27.0 mm (1.06 in) |
| Valve steam diameter (INTAKE): | 6.960-6.975 mm (0.274-0.2746 in) |
| Valve steam diameter (EXHAUST): | 6.960-6.975 mm (0.274-0.2746 in) |
| Valve length (INTAKE): | 101.5 mm (3.99 in) |
| Valve length (EXHAUST): | 101.5 mm (3.99 in) |
| Valve spring free length (INTAKE): | 37.0-37.5 mm (1.4567-1.4764 in) |
| Valve spring free length (EXHAUST): | 37.0-37.5 mm (1.4567-1.4764 in) |
| Camshaft lobe height (INTAKE): | 28.80 mm (1.1339 in) |
| Camshaft lobe height (EXHAUST): | 29.00 mm (1.1417 in) |
| Camshaft journal diameter : | 35.934-35.950 mm (1.4147-1.4154 in) |
| Timing Gear | |
| Crank Gear to Idle Gear 1 (backlash): | 0.0320-0.115 mm (0.00126-0.00452 in) |
| Idle Gear 1 to Cam Gear (backlash): | 0.0360-0.114 mm (0.00142-0.00448 in) |
| Idle Gear 1 to Injection Pump Gear (backlash): | 0.0340-0.116 mm (0.00134-0.00456 in) |
| Idle Gear 1 to Idle Gear 2 (backlash): | 0.0330-0.117 mm (0.00130-0.00460 in) |
| Idle Gear 2 to Governor Gear (backlash): | 0.0300-0.117 mm (0.00119-0.00460 in) |
Tightening torque
| Tightening torque specs | |
| Cylinder head cover screw (M7x1.0): | 6.9-8.8 Nm (5.1-6.5 lb-ft) |
| Cylinder head screw (M10x1.25): | 63.7-68.6 Nm (47.0-50.6 lb-ft) |
| Main bearing case screw 1 (M8x1.25): | 29.4-34.3 Nm (21.7-25.3 lb-ft) |
| Main bearing case screw 2 (M9x1.25): | 49.0-53.9 Nm (36.2-39.8 lb-ft) |
| Flywheel screw (M10x1.25): | 53.9-58.8 Nm (39.8-43.4 lb-ft) |
| Connecting rod screw (M8x1.0): | 41.2-46.1 Nm (30.4-34.0 lb-ft) |
| Rocker arm bracket nuts (M7x1.0): | 21.6-26.5 Nm (15.9-19.5 lb-ft) |
Service Data
| Engine | |
| Idle speed: | 900 rpm |
| Maximum speed: | 3,000-3,800 rpm (depending on modification) |
| Cylinder compression: | 3.73 to 4.11 MPa, 38.0 to 42.0 kgf/cm2, 541 to 597 psi |
| Valve clearance | |
| Intake valve clearance: | 0.145-0.185 mm (0.0057-0.0073 in) |
| Exhaust valve clearance: | 0.145-0.185 mm (0.0057-0.0073 in) |
| Oil system | |
| Lubrication system: | Forced lubrication by trochoid pump |
| Oil type: | CF or higher |
| Recommended oil: | SAE 10W-30, 10W-40 |
| Oil capacity: | 5.7 liters (6.0 US.qts, 5.0 Imp. qts) |
| Oil pressure: | At idle speed: 49 MPa (0.5 kgf/cm2, 7 psi) At rated speed: 196 to 441 MPa (2.0-4.5 kgf/cm2, 28 to 64 psi) |
| Oil filter: | Full flow paper filter (Cartridge type) |
| Oil pressure indicating: | Electrical type switch |
| Oil and oil filter change interval: | Every 200 hours |
| Fuel system | |
| Fuel injection pump: | Bosch MD type mini fuel injection pump |
| Injection nozzle: | Mini Nozzle (DNOPD) |
| Firing order: | 1-2-3 |
| Injection pressure: | 13.73 to 14.70 MPa; 140.0 to 150.0 kgf/cm2; 1992 to 2133 psi |
| Electrical system | |
| Battery: | 12V, 65Ah or equivalent |
| Starting motor: | D1305-E3B: 12 V, 1.1 kW D1305-E4B: 12 V, 1.2 kW |
| Charging alternator: | 12 V, 480 W |
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