Kubota D722 vs D902: Key Differences, Shared Parts, and What to Order

Short version on Kubota D722 vs D902: Both engines are part of Kubota's Super Mini Series. The D902 is the bigger-bore, bigger-displacement engine. That size difference is exactly why some parts swap between them and others don't. If you order by "it's a small Kubota 3-cylinder," you'll end up with the wrong piston or head gasket. Order by the number stamped on your engine and your part instead.

Quick Answer

• Same family, different size. Both are 3-cylinder, water-cooled, naturally aspirated Kubota Super Mini Series diesels. The D902 is the larger-displacement relative of the D722.

• D722: 719 cc, 67 mm bore, 68 mm stroke.

• D902: 898 cc, 72 mm bore, 73.6 mm stroke.

• Parts that may be shared: a lot of some service and wear items may be shared — verify individually, like oil filters and glow plugs. Some connecting rods are listed for both.

• What does NOT swap: anything tied to bore or displacement, mainly pistons, rings, and head gaskets. Those are engine-specific.

• Rule of thumb: Before ordering, confirm the complete engine model, engine serial number, equipment model and original part number.

Key Differences Between the D722 and D902

These two share a design. Both are inline 3-cylinder, water-cooled, naturally aspirated diesels from Kubota's Super Mini Series. They look alike, they mount in similar equipment, and a lot of the supporting hardware is common. The difference that matters is displacement.

Here's where they split:

• Displacement: D722 is 719 cc; D902 is 898 cc. That's about 179 cc more in the D902, roughly a 25% jump.

• Bore: D722 runs a 67 mm bore; D902 runs 72 mm. The different bore, stroke and piston design mean D722 and D902 pistons and rings are not interchangeable.

• Stroke: D722 is 68 mm; D902 is 73.6 mm.

• Power: more displacement means more output. The D902 makes more horsepower and torque than the D722 at the same rpm. Exact figures depend on your variant and rating, so read them off your spec plate rather than a chart.

Where they're the same: the general architecture, the 3-cylinder layout, the cooling setup, and a good chunk of the accessory and service parts. That overlap is real, and it's why the "are these the same engine?" question keeps coming up. They're not the same engine, but they are close relatives that share a parts shelf in places.

Shared Parts vs. Engine-Specific Parts (By Part)

This is the part that saves you a return. Some items are listed for both engines; others are cut for one bore and will not work in the other. Below is how it breaks down, with real parts you can check against your own. Whatever you pick, confirm the number stamped on your part before ordering, because fitment can vary by year, serial, and equipment.

Parts that may be shared — verify individually

• Oil filter. A common spin-on filter is listed for both the D722 and D902. See the Kubota D722 D902 Oil Filter HH150-32430 15853-32430. Same filter thread and gasket across the family in most cases.

• Glow plugs. Glow plugs commonly cross several Super Mini Series engines, so a D722 and a D902 will often take the same plug. This is a "confirm the stamped number" item, since plug thread and length have to match your head. Check the number on your old plug before ordering.

• Connecting rod. Certain replacement rods are listed for both engines. Arko's Kubota Connecting Rod D722 D782 D902 Z482 WG972 lists both the D722 and D902 in its fitment. Not every rod carries across, so confirm the original part number and the engine serial number, along with the journal size, before ordering.

Parts that are engine-specific (do not assume they swap)

• Pistons and rings. These follow the bore, so they are not interchangeable. The D722 uses a 67 mm piston and ring set; the D902's 72 mm parts will not fit. If you're doing the bottom end on a D722, the Kubota D722 Engine Overhaul Rebuild Kit 16863-99366 16851-21114 16853-21050 is built for that bore. Do not order it for a D902.

• Head gasket. Different bore means a different fire ring, so the gaskets are not the same part. The D722 uses Kubota D722 Cylinder Head Gasket 16871-03310 (also listed for the D782), while the D902 uses Kubota D902 Cylinder Head Gasket 1G962-03313. Two different part numbers for a reason.

• Cylinder head. The head is machined for the engine's bore and ports, so it's engine-specific too. For the bigger engine, see the Kubota D902 Cylinder Head 1G962-03040. A D722 head is a separate part.

The pattern is simple: bore-and-displacement parts are specific to each engine. Some maintenance items and selected components may be shared, but every part must be verified individually. When in doubt, read the stamped number and match it. If you can't find a number or can't read it, send us a photo and we'll sort it out.

FAQ

Will D722 parts fit a D902?

Some will, some won't. Some oil filters and glow plugs may be listed for both engines, but fitment must be verified by part number and engine serial number. Certain connecting rods may be listed for both applications; confirm the original part number and journal size. But anything tied to the bore, mainly pistons, rings, head gaskets, and the cylinder head, is engine-specific. A D722 piston (67 mm) will not fit a D902 (72 mm). Confirm the number on your part before ordering.

Is the D902 just a bigger D722?

In plain terms, yes, that's the easiest way to think about it. Both are 3-cylinder engines from Kubota's Super Mini Series. The D902 has a larger bore and stroke, which gives it 898 cc versus the D722's 719 cc and more power. The family resemblance is why they may share selected service parts and components, and the size gap is why the internals differ.

How do I tell which engine I actually have?

Read the model and serial off the engine's ID plate or the stamped pad on the block. The model number will say D722 or D902 right on it. Don't guess from the equipment model.

Can I use a D902 head gasket on a D722?

No. The D722 and D902 have different bore sizes and use different head-gasket part numbers. The commonly listed D722 gasket is 16871-03310, while the D902 uses 1G962-03313. They should not be treated as substitutes. Confirm by engine serial number before ordering.

Do the D722 and D902 use the same oil filter?

They are commonly listed with the same spin-on oil-filter application, including HH150-32430. However, confirm the current filter number and engine serial number before ordering. Follow the Kubota service manual for the correct engine-oil specification and viscosity.

Order the Right Part the First Time

The D722 and D902 are close enough to share a shelf and different enough to burn you if you order by family instead of by number. Match the stamped part number, lean on the shared items when they truly cross, and keep the bore-specific parts engine-specific. Not sure which side of the line your part falls on? Send us your engine model and the number stamped on your part and we'll match it.

Arko Tractor Parts Team