Shibaura ST321
The Shibaura ST321 is a tractor produced by Shibaura. It is equipped with a 61.3 ci 1.0 L engine. The listed engine power is Diesel (listed): 21 hp / 15.7 kW. Transmission: infinite forward and reverse (2-range). Operating weight: 1649 to 1662 pounds.
Engine Power
Diesel (listed): 21 hp / 15.7 kW
Fuel & Capacities
5.3 gal
20.1 L
Transmission
infinite forward and reverse (2-range)
Operating Weight
1649 to 1662 pounds
Overview
 | ST SeriesCompact Utility tractor |
|---|---|
ST Series | |
Compact Utility tractor | |
Production | |
|---|---|
Manufacturer | Shibaura |
Compact Utility tractor | |
Built in Matsumoto, Japan | |
Shibaura ST321 Engine | |
|---|---|
Shiabaura 1.0L 3-cyl diesel | |
Engine details ...  |
Shibaura ST321 Power | |
|---|---|
Engine | 21 hp
15.7 kW |
PTO (claimed) | 17 hp
12.7 kW |
Mechanical | |
|---|---|
Four-wheel drive | |
Differential lock | mechanical rear |
Power steering | |
Wet disc brakes | |
Two-post folding ROPS. | |
Capacity | |
|---|---|
Fuel | 5.3 gal
20.1 L |
Hydraulic system | 4.2 gal
15.9 L |
Hydraulics | |
|---|---|
Type | open center |
Capacity | 4.2 gal
15.9 L |
Pressure | 1849 psi
127.5 bar |
Pump flow | 4.9 gpm
18.5 lpm |
Tractor hitch | |
|---|---|
Rear Type | I |
Rear lift | 1474 lbs
668 kg |
Power Take-off (PTO) | |
|---|---|
Gear Rear PTO | transmission |
Hydro Rear PTO | live |
Rear PTO Type | 540 (1.375) |
Gear Engine RPM | 588@2600 |
Hydro Engine RPM | 561@2600 |
Mid PTO | optional |
Mid PTO Type | 2000 |
Gear Engine RPM | 2139@2600 |
Hydro Engine RPM | 2040@2600 |
Dimensions & Tires | |
|---|---|
Wheelbase | 55.3 inches
140 cm |
Weight | 1649 to 1662 pounds |
Front tire | 6-12 |
Rear tire | 9.5-16 |
Full dimensions and tires ...  | |
Electrical | |
|---|---|
Ground | negative |
Charging system | alternator |
Charging amps | 40 |
Charging volts | 14 |
Battery volts | 12 |
References | |
|---|---|
 | |
ST318 ST321 ST324 Workshop Manual |
Engine
Engine Detail — 61.3 ci / 1.0 L Diesel
Manufacturer | Shiabaura S773 |
Fuel Type | Diesel |
Configuration | 3-cylinder, liquid-cooled |
Displacement | 61.3 ci
1.0 L |
Bore/Stroke | 3.03x2.83 inches
77 x 72 mm |
Power | 21 hp
15.7 kW |
Compression | 23:1 |
Rated RPM | 2600 |
Starter | electric |
Starter volts | 12 |
Oil capacity | 3.5 qts
3.3 L |
Coolant capacity | 3.7 qts
3.5 L |
Transmission
Transmission options | |
|---|---|
9-speed gear | |
hydrostatic |
Transmission — 9 forward and 3 reverse gear
Type | gear |
Gears | 9 forward and 3 reverse |
Clutch | dry disc |
With 9.5-16 rear tires. | |
 | |
Transmission — infinite forward and reverse (2-range) hydrostatic
Type | hydrostatic |
Gears | infinite forward and reverse (2-range) |
With 29x12.00-15 R3 rear tires. | |
 | |
Dimensions
Shibaura ST321 Tires | |
|---|---|
Ag front | 6-12 |
Ag rear | 9.5-16 |
Lawn/turf front | 20x8.00-10 |
Lawn/turf rear | 29x12.00-15 |
Dimensions | |
|---|---|
Wheelbase | 55.3 inches
140 cm |
Length | 107.4 inches
272 cm |
Gear Width | 44.8 inches
113 cm |
Hydro Width | 46.8 inches
118 cm |
Gear Height (ROPS) | 90 inches
228 cm |
Hydro Height (ROPS) | 88.2 inches
224 cm |
Gear Weight | 1662 lbs
753 kg |
Hydro Weight | 1649 lbs
747 kg |
Gear Clearance (front axle) | 10.6 inches
26 cm |
Hydro Clearance (front axle) | 8.8 inches
22 cm |
Front tread | 33.3 inches
84 cm |
Rear tread | 35.3 to 37.7 inches
89 to 95 cm |
Photos
Shibaura ST321 tractor photo
Recommended Implements & Sizing Guide
Engineering recommendations for Shibaura ST321 based on its 21 HP power envelope and ASAE agricultural standards.
| Implement & Operation | Recommended Size | Workload Rating | Engineering Notes |
|---|---|---|---|
Moldboard PlowPrimary Tillage | 1 to 2 Bottom (12")1 - 2 铧 (30 cm) | Light Duty | Ideal for garden plots and light sandy soil. |
Rotary Cutter / MowerMowing & Clearing | 4 ft (48 in)1.2 m | Light Duty | Pasture clipping and light brush under 1" diameter. |
Rotary TillerSeedbed Prep | 42 to 48 in105 - 120 cm | Light Duty | Covers compact tractor tire width. |
Disc HarrowSecondary Tillage | 5 to 6 ft (16-18" discs)1.5 - 1.8 m (40-45 cm 耙片) | Light Duty | Small acreage soil break-up and secondary aeration. |
Sizing & Soil Condition NoteActual implement sizing varies depending on local soil conditions (heavy clay vs sandy loam), field slope, and operating speed. Heavy tillage implements may require front ballast weights and wheel weights.
Fluids, Capacities & Working Autonomy
Standard fluid requirements, service intervals, and continuous runtime estimates for Shibaura ST321.
Estimated Continuous Field Runtime: 4.9 hrs
Approximately 4.9 hours of continuous field operation at ~75% rated power on a full tank (5.3 gal / 20.1 L).
Estimated 75% Load Fuel Burn~1.1 gal/hr (4.1 L/hr)
Engine Crankcase Oil
SAE 15W-40 (Heavy Duty Diesel)
Standard Spec: API CK-4 / CJ-4 Heavy Duty
Service Interval: 150 – 250 Hours
Transmission & Hydraulic System
UTTO (Universal Tractor Transmission Oil)
Standard Spec: ISO VG 46 / 68 (Wet Brake & Trans Compatible)
Service Interval: 600 – 1000 Hours
Engine Cooling System
50/50 Ethylene Glycol Pre-mix
Standard Spec: ASTM D6210 / Heavy-Duty OAT Antifreeze
Service Interval: 2 Years / 1500 Hours
Shibaura ST321 Specification Unit Converter
Convert power, fluid capacities, and operating weights between metric and imperial standards for Shibaura ST321.
Converted Equivalents:
Horsepower (HP)21 hp
Kilowatts (kW)15.7 kW
Metric Horsepower (PS / CV)21.3 PS
Direct Competitor Comparison
Compare Shibaura ST321 against same-era industry alternatives in the same horsepower class.
Current Model
Shibaura
Shibaura ST321
Engine Power:Diesel (listed): 21 hp / 15.7 kW
★ Baseline Reference
International HarvesterMarket Competitor
International Harvester D-219
Engine Power:19
Production Years:1962 - 1966
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