Kubota D1105 vs D722 is not a same-size engine comparison. In the official E4B specifications, both are naturally aspirated three-cylinder indirect-injection diesels, but the D1105 has substantially more displacement, output, torque, mass, and overall length. Those differences affect packaging and duty planning, while exact parts still require model-suffix, serial-number, and part-number verification.
Kubota D1105 vs D722 specifications
| Specification | D1105-E4B | D722-E4B | Why it matters |
|---|---|---|---|
| Series | Kubota 05 Series | Kubota Super Mini Series | Different engine families mean separate parts catalogs and identification paths. |
| Type | Vertical, water-cooled, four-cycle diesel | Vertical, water-cooled, four-cycle diesel | Shared general architecture does not establish parts interchangeability. |
| Cylinders | 3 | 3 | Cylinder count alone is not enough to identify either model. |
| Bore x stroke | 78.0 x 78.4 mm | 67.0 x 68.0 mm | Different dimensions affect pistons, rings, liners, block work, and displacement. |
| Displacement | 1.123 L | 0.719 L | The D1105 has about 56 percent more displacement than the D722. |
| Rated output | 18.5 kW (24.8 HP) at 3000 rpm | 14.9 kW (20.0 HP) at 3600 rpm | These are SAE J1995 gross-intermittent figures for the named variants, not universal installed ratings. |
| Maximum torque | 71.5 Nm at 2200 rpm | 45.8 Nm at 2600 rpm | Application load and speed requirements must be evaluated with the equipment manufacturer. |
| Combustion / fuel system | Indirect injection / in-line pump | Indirect injection / in-line pump | Similar system descriptions do not mean pumps, injectors, or settings are shared. |
| Published L x W x H | 480 x 396 x 605 mm | 407 x 386 x 564 mm | Kubota states that dimensions depend on completed specifications; mounting and accessories still require direct measurement. |
| Published dry weight | 93 kg | 63 kg | The D1105 reference is 30 kg heavier before equipment-side differences are considered. |
Core design and size differences
Both engines use three cylinders, water cooling, natural aspiration, indirect injection, and an in-line injection pump in the cited E4B specifications. The important difference is scale. The D1105 uses a 78.0 mm bore and 78.4 mm stroke, while the D722 uses a 67.0 mm bore and 68.0 mm stroke. That produces the large displacement gap shown above and explains why internal parts must not be chosen from cylinder count or appearance.
The standard-specification envelope also shows the D1105 as longer, slightly wider, taller, and heavier. These published dimensions exclude the cooling fan and may not represent the final equipment package. A repower or replacement decision must also account for mounts, shaft or flywheel details, cooling airflow, exhaust routing, intake, wiring, controls, fuel plumbing, accessory drive, service clearance, emissions requirements, and equipment approval.
D1105 planning profile
The official data show the D1105-E4B providing more displacement, rated output, and maximum torque, with a larger and heavier standard package. It may suit a requirement that genuinely needs those characteristics, but only after the complete equipment interface and rating are confirmed.
D722 planning profile
The official data show the D722-E4B as the smaller and lighter reference. Compact packaging can be useful, but the engine still must meet the equipment's load, speed, cooling, duty-cycle, and regulatory requirements.
Power, weight, and application decisions
Do not reduce the choice to horsepower alone. The published D1105 and D722 ratings occur at different speeds, and the torque peaks are also listed at different speeds. The equipment may require a specific governing strategy, continuous or intermittent rating, transient response, accessory load, cooling capacity, and operating envelope. A higher published number does not prove that an engine is a safe replacement in a particular machine.
For an existing installation, identify the original engine and consult the equipment manufacturer or a qualified Kubota engine distributor before substitution. For a new integration, use the current technical package and engineering review. The correct question is not simply which engine is better; it is which verified configuration meets the documented load, packaging, control, durability, service, and compliance requirements.
How to identify D1105 and D722 correctly
Kubota Engine America says the serial number is stamped on the block, with location varying by engine series. Its identification page places the Super Mini Series stamping near the injection-pump fixing point and gives separate locations for the 05 Series. It also warns that an emissions label is not the engine serial-number reference needed for parts identification.
Record the complete serial number, the information on the serial-number label, the equipment manufacturer and model, and clear photos of the engine from several sides. Kubota's current model-name guide explains that D denotes a three-cylinder diesel and that the suffix identifies a model variation. It also notes that the full model name is obtained from the Illustrated Parts List rather than assumed from a visible casting or emissions label.
- Photograph the serial-number stamping and label without cropping characters.
- Record the equipment brand, model, application, and existing engine history.
- Capture the injection-pump side, flywheel side, front drive, manifolds, oil pan, and external plumbing.
- Retain old part numbers, superseded numbers, dimensions, and removed-part photos.
- Use the current Illustrated Parts List and serial breaks before approving an order.
For maintenance-specific identification examples, use the published D1105 oil-capacity and service guide and D722 oil-capacity and maintenance guide. Each article keeps capacity and service guidance tied to its own engine and configuration.
Parts differences that matter during repair
The bore and stroke differences immediately show why pistons, rings, and cylinder work are model-specific. Piston crown geometry, pin dimensions, ring grooves, liner or bore construction, compression height, and machining choices require exact documentation and measurements. Even where two parts look similar in a product photo, visual similarity is not compatibility evidence.
Bearings, thrust components, crankshaft dimensions, gaskets, valve-train parts, pumps, injectors, and external components also need model-specific checking. The published D1105 rebuild-parts checklist and D722 rebuild-parts guide explain how to build separate teardown and measurement records.
Gasket kits, oil pumps, and water pumps
A gasket kit should be checked piece by piece. Compare the head-gasket openings, sealing layers, cover shapes, oil and coolant passages, O-rings, seals, and quantities with the removed parts and the current parts list. The ACTIVE D1105 overhaul gasket-kit listing and D722 overhaul gasket-kit listing are deliberately different commercial references; neither establishes universal coverage for every suffix or serial range.
Pumps are also not selected from family resemblance. For a D1105 lubrication repair, compare the old component, drive, housing, pressure history, and current parts data with the ACTIVE D1105 oil-pump listing. For a D722 cooling repair, diagnose the complete circuit and compare mounting, ports, drive details, and old numbers with the ACTIVE D722 water-pump listing.
Are D1105 and D722 parts interchangeable?
Do not assume interchangeability. The official specifications already show different bores, strokes, displacement, dimensions, mass, output, and torque. Internal components must match the exact model and repair dimensions, while external components must match the part number and physical interface. A common brand, cylinder count, injection type, bolt pattern that appears similar, or seller keyword is not enough.
A valid substitution or supersession needs current documentation for the exact engine, serial break, and application. If a supplier proposes an alternative number, request the cross-reference basis and compare the old part, dimensions, connectors, drive, passages, and included hardware before installation.
Which route fits your repair scenario?
Maintaining the installed engine
Stay with the identified model path. Use its service guide, parts list, serial information, and measured condition. Order only after fluid, cooling, lubrication, and internal findings are documented.
Rebuilding after wear or damage
Use the dedicated D1105 or D722 rebuild checklist. Let teardown measurements and the machine-shop plan determine piston, ring, liner, bearing, gasket, and pump requirements.
Considering an engine replacement
Obtain engineering approval for mounts, output, torque, speed, cooling, controls, emissions, accessories, service access, and the equipment manufacturer's requirements.
Ordering an uncertain loose part
Pause the purchase. Collect the engine serial number, application, old part number, markings, dimensions, photos, and quantity, then verify against current documentation.
What the comparison table cannot decide
A specification table is useful for separating the two base-engine models, but it cannot approve an equipment installation or a parts order. It does not show the final radiator, fan, air cleaner, exhaust, wiring harness, control panel, flywheel housing, PTO, alternator, oil pan, mounting feet, or OEM-specific attachments. It also does not show the service history, wear condition, previous machining, or undocumented modifications on an engine that is already in use.
Published rated output is especially easy to misuse. The cited values use the same SAE J1995 gross-intermittent basis, which makes the official sheets useful for a controlled comparison, but an equipment requirement may use a different rating, speed, ambient condition, altitude correction, accessory load, or duty cycle. Continuous operation, transient loading, sound limits, cooling reserve, emissions certification, and local compliance may change the engineering decision. Confirm the completed specification rather than copying the largest number from a catalog.
Likewise, the published dimensions and dry weights are reference values. Kubota notes that they depend on completed specifications. Before a replacement or repower, measure the actual installed engine and document the crankshaft centerline, mounting points, shaft and flywheel interfaces, service clearances, intake and exhaust routing, radiator connections, controls, and lifting or structural limits. A physically smaller engine is not automatically a direct fit, and a more powerful engine is not automatically an acceptable upgrade.
Create a decision record before buying
A short decision record helps the supplier, technician, and machine owner work from the same evidence. Start with the engine serial number and the full equipment identity. Attach the official specification page used for comparison, label the exact variant, and state whether the job is routine maintenance, a measured rebuild, a component repair, or a proposed replacement. List every proposed product URL beside the old part number, dimensions, quantity, and reason for replacement.
For a rebuild, include compression or pressure findings, fluid contamination, bore and journal measurements, head and block inspection, and the machine-shop recommendation. For an external component, include mounting, drive, connector, port, rotation, and clearance details. Mark unresolved lines as pending instead of converting an assumption into a purchase. Keep the supplier's written confirmation with the repair file, and inspect received parts against that record before machining or installation.
Verify D1105 or D722 parts before ordering
Send the complete engine model, serial number, equipment model, old part number, measurements, and clear photos. For internal parts, include teardown findings and the machine-shop plan. This separates the D1105 and D722 order paths and reduces wrong-part risk.
Frequently asked questions
What are the main differences between Kubota D1105 and D722?
For the official E4B variants, the D1105 has 1.123 L displacement versus 0.719 L for the D722, with larger bore and stroke, higher published output and torque, and greater standard-specification size and dry weight.
How can I identify which engine I have?
Record the serial-number stamping and label, equipment details, and engine photos. Use Kubota's serial-number guidance and the current Illustrated Parts List; do not rely only on an emissions label or visual resemblance.
Which systems or parts differ between D1105 and D722?
Internal dimensions, pistons, rings, cylinder work, bearings, gaskets, pumps, injectors, valve-train items, and external interfaces can differ. Verify each part number and dimension for the exact model and serial range.
Are D1105 and D722 parts interchangeable?
Interchangeability should not be assumed. Use current parts documentation, serial breaks, old part numbers, measurements, and physical-interface checks before accepting any substitution or supersession.
What information should I send before ordering parts?
Send the complete engine model and suffix, serial number, equipment model, old part number, quantity, dimensions, failure history, and clear photos. Include machine-shop measurements for internal parts.