The Honda GD321 is a (317 cc, 19.34 cu-in) single-cylinder air-cooled 4-stroke internal combustion diesel engine with horizontal shaft, manufactured by Honda Motor Company for general-purpose applications.
This engine has a single-cylinder; overhead valves and direct injection combustion system. The motor used Zexel PFRIKX fuel injection pump and Zexel DLLA-P injection nozzle. The GD321 engine could be equipped with recoil starter and starter motor, or recoil starter only.
The GD321 has a 76.0 mm (2.99 in) cylinder bore and 70.0 mm (2.76 in) piston stroke. The compression ratio is 20:1 for North America type and 19:1 for other engines. It produced 7.0 HP (5.2 kW) of maximum output and 15.7 N·m (1.6 kg·m, 11.57 ft·lb) at 2,500 rpm of torque.
General information
| Engine Specifications | |
| Model | GD321 |
| Type | 4-stroke, OHV, single cylinder |
| Displacement | 317 cm 3 (19.34 cu-in) |
| Max. horsepower |
S,Q,W,V,P type: 7.0 HP (5.2 kW) at 3,600 rpm B type: 6.0 HP (4.4 kW) at 3,000 rpm L type: 6.8 HP (5.0 kW) at 1,800 rpm |
| Max. torque (crank PTO) |
S,Q,W,V,P type:15.7 N·m (1.6 kg·m, 11.57 ft·lb) at 2,500 rpm B type: 15.7 N·m (1.6 kg·m, 11.57 ft·lb) at 1,800 rpm L type: 30.4 N·m (3.1 kg·m, 23 ft·lb) at 1,250 rpm |
| Cooling system | Forced-air |
| Lubricating system | Forced spray |
| Starting system | Recoil starter or starter motor |
| Stoping system | Fuel cut with speed control lower (Stop lever) |
| Fuel used | Diesel fuel |
| Fuel tank capacity | 4.6 l (1.21 US. Gal, 1.2 Imp. Gal.) |
| Fuel consumption |
S,Q,W,V,P type: 180 g/HPh B type: 196 g/HPh |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Cylinder Block and Head
| Cylinder block | ||
| Compression ratio: | 19:1, 20:1 | |
| Bore x Stroke | 76 mm X 70 mm (2.99 x 2.76 in) | |
| Sleeve internal diameter | 76.000-76.017 mm (2.9921-2.9928 in) | |
| Piston skirt outer diameter | 75.940-75.960 mm (2.9898-2.9905 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Ring side clearance | Top | 0.065-0.095 mm (0.0026-0.0037 in) |
| Second | 0.055-0.085 mm (0.0022-0.0033 in) | |
| Oil | 0.020-0.055 mm (0.0008-0.0022 in) | |
| Ring end gap | Top | 0.20-0.35 mm (0.008-0.014 in) |
| Second | 0.20-0.35 mm (0.008-0.014 in) | |
| Oil | 0.20-0.40 mm (0.008-0.016 in) | |
| Ring width | Top | 1.990-1.975 mm (0.0783-0.0778 in) |
| Second | 1.990-1.975 mm (0.0783-0.0778 in) | |
| Oil | 3.990-3.970 mm (0.1571-0.01563 in) | |
| Connecting rod small end ID | 20.010-20.028 mm (0.7878-0.7885 in) | |
| Connecting rod big end ID | 41.000-41.024 mm (1.6142-1.6151 in) | |
| Crankpin outer diameter | 37.976-38.000 mm (1.4951-1.4961 in) | |
| Main journal outer diameter | 46.970-46.994 mm (1.8492-1.8502 in) | |
| Cylinder Head | ||
| Distortion of cylinder head | 0.05 mm (0.002 in) | |
| Valve Arrangement: | OHV | |
| Valves: | 2 | |
| Stem outer diameter (standard): | INTAKE | 6.590-6.575 mm (0.2594-0.2589 in) |
| EXHAUST | 6.550-6.540 mm (0.2579-0.2575 in) | |
| Guide internal diameter | INTAKE / EXHAUST | 6.600-6.615 mm (0.2598-0.2604 in) |
| Spring free length | 33.7 mm (1.33 in) | |
| Cam lobe height | INTAKE / EXHAUST | 41.022 mm (1.6150 in) |
| Valve rocker arm internal diameter | INTAKE / EXHAUST | 16.000-16.018 mm (0.6300-0.6306 in) |
| Rocker arm shaft outer diameter | INTAKE / EXHAUST | 15.984-15.966 mm (0.6293-0.6286 in) |
Tightening torque specs
| Tightening torque specs | |
| Cylinder head bolts | 43 Nm; 4.3 kg·m; 31 ft·lb |
| Cylinder head nuts | 11 Nm; 1.1 kg·m; 8 ft·lb |
| Rocker arm shaft nuts | 11 Nm; 1.1 kg·m; 8 ft·lb |
| Tappet adjusting nuts | 9 Nm; 0.9 kg·m; 6.5 ft·lb |
| Oil pan bolt bolts |
M11: 71 Nm; 7.1 kg·m; 51 ft·lb M8: 22 Nm; 2.2 kg·m; 16 ft·lb |
| Connecting rod cap nuts | 32 Nm; 3.2 kg·m; 23 ft·lb |
| Relief valve | 33 Nm; 3.3 kg·m; 24 ft·lb |
| Drain plug bolt | 33 Nm; 3.3 kg·m; 24 ft·lb |
| Flywheel nut | 250 Nm; 25.0 kg·m; 180 ft·lb |
| Injection nozzle | 10 Nm; 1.0 kg·m; 7 ft·lb |
| Air breather joint nuts | 18 Nm; 1.8 kg·m; 13 ft·lb |
| Fuel injection pump bolts | 22 Nm; 2.2 kg·m; 16 ft·lb |
| Fuel joint bolts | 28 Nm; 2.8 kg·m; 20 ft·lb |
| Air breather bolt | 18 Nm; 1.8 kg·m; 13 ft·lb |
| Fuel pipe nuts | 20 Nm; 2.0 kg·m; 14 ft·lb |
| Muffler nuts, bolts | 22 Nm; 2.2 kg·m; 16 ft·lb |
| Fuel tank bolts | 11 Nm; 1.1 kg·m; 18 ft·lb |
| Fuel filter bolts | 11 Nm; 1.1 kg·m; 18 ft·lb |
| Drain bolt | 11 Nm; 1.1 kg·m; 18 ft·lb |
| Others | |
| 5 mm bolts, nuts | 5.0 Nm; 0.50 kg·m; 4.0 ft·lb |
| 6 mm bolts, nuts | 10 Nm; 1.0 kg·m; 7 ft·lb |
| 8 mm bolts, nuts | 21 Nm; 2.1 kg·m; 15 ft·lb |
| 10 mm bolts, nuts | 35 Nm; 3.5 kg·m; 25 ft·lb |
| 12 mm bolts, nuts | 60 Nm; 6.0 kg·m; 44 ft·lb |
Service Information
| Engine | |
| Maximum speed | 3,750 ± 150 rpm |
| Idle speed | 1,400 ± 150 rpm |
| Cylinder compression | 26.0 kg/cm2 (370 psi) at 300 rpm |
| Valve clearance | |
| Intake valve | 0.15 ± 0.02 (0.006 ± 0.00078) |
| Exhaust valve | 0.15 ± 0.02 (0.006 ± 0.00078) |
| Oil system | |
| Oil type | Diesel oil (API Service Classification CC or CD) |
| Recommended oil | SAE 10W-30 |
| Oil capacity | 1.15 l (1.21 US. qt, 1.01 Imp. qt.) |
| Oil pressure | 3.9-5.2 kg/cm2 (55.5-74.0 psi) at 3,600 rpm |
| Generator | |
| Resistance | 2.0 ±0.5 Ω |
| Starter motor | |
| Brush length | 10 mm (0.39 in) |
| Mica depth | 0.4-0.5 mm (0.016-0.020 in) |
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