Kubota D1305

The Kubota D1305 is a 1.3 L (1,261 cc, 76.95 cu-in) straight-three, water-cooled naturally aspirated diesel engine from Kubota 05-series.

The D1305 engine has a spherical type сombustion сhamber with glow plug, Bosch MD type mini fuel injection pump, and mini injection nozzle (DNOPD). The compression ratio rating is 24.0:1. The cylinder bore and the piston stroke are 78.0 mm (3.07 in) and 88.0 mm (3.46 in), respectively.

The Kubota D1305-E3B diesel engine produces up to 28.6 PS (21.0 KW; 28.2 HP) at 3,000 rpm of net horsepower 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 breakdown of the engine code is as follows:

• D – 3-cylinders
• 13 – Approximate displacement 1,300 cc
• 05 – 05-series

General information

Engine Specifications
Engine code	D1305-E3B, -E4B
Layout	Straight-3, vertical diesel engine
Fuel type	Diesel
Production	–
Displacement	1.3 L, 1,261 cm3 (76.95 cu in)
Fuel injection pump	Bosch MD type mini fuel injection pump
Fuel nozzle	Mini nozzle (DNOPD)
Starting system	Electric starting (12V, 1.1kW or 1.2kW)
Starting support device	Glow plug in combustion chamber
Governor	All speed mechanical governor
Power adder	None
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*
Torque output	–
Firing order	1-2-3
Dimensions (L x W x H):	498 x 397 x 590 mm (19.6 x 15.6 x 23.0 in)
Weight	95 kg (210 lbs)

*-may be differ depending on engine modification

Cylinder block

Cylinder block
Compression ratio:		24.0:1
Cylinder bore:		78.0 mm (3.07 in)
Piston stroke:		88.0 mm (3.46 in)
Number of piston rings (compression / oil):		2 / 1
Cylinder inner diameter:		78.000-78.019 mm (3.0709-3.0716 in)
Piston skirt diameter		–
Piston ring side clearance:	Second	0.085-0.112 mm (0.0033-0.0044 in)
	Oil	0.020-0.060 mm (0.0008-0.0023 in)
Piston ring end gap:	Top	0.200-0.350 mm (0.0079-0.0130 in)
	Second	0.300-0.450 mm (0.0118-0.0177 in)
	Oil	0.300-0.550 mm (0.0120-0.0210 in)
Piston pin outer diameter		22.002-22.011 mm (0.8662-0.8666 in)
Crankshaft main journal diameter:		51.921-51.940 mm (2.0442-2.0448 in)
Crankpin diameter:		39.959-39.975 mm (1.5732-1.5738 in)

Cylinder head

Cylinder head
Valve Arrangement:		OHV, gear drive
Valves:		6 (2 valves per cylinder)
Valve head diameter:	INTAKE	–
	EXHAUST	–
Valve length:	INTAKE	101.5 mm (3.99 in)
	EXHAUST	101.5 mm (3.99 in)
Valve stem diameter:	INTAKE	6.960-6.975 mm (0.274-0.2746 in)
	EXHAUST	6.960-6.975 mm (0.274-0.2746 in)
Valve spring free length:	INTAKE	37.0-37.5 mm (1.4567-1.4764 in)
	EXHAUST	37.0-37.5 mm (1.4567-1.4764 in)
Camshaft lobe height:	INTAKE	28.80 mm (1.1339 in)
	EXHAUST	29.00 mm (1.1417 in)
Camshaft journal diameter:		35.934-35.950 mm (1.4147-1.4154 in)

Maintenance data

Valve clearance
Intake valve	0.145-0.185 mm (0.0057-0.0073 in)
Exhaust valve	0.145-0.185 mm (0.0057-0.0073 in)
Compression pressure
Standard	3.73 to 4.11 MPa, 38.0 to 42.0 kgf/cm2, 541 to 597 psi
Oil system
Recommended engine oil	CF or higher
SAE Viscosity Number	SAE 10W-30, 10W-40
Engine oil capacity	5.7 liters (6.0 US.qts, 5.0 Imp. qts)
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