Kubota 1J770-50605 Common Rail Assembly for V2607-CR / V3307-CR (Genuine)

Genuine Kubota common rail assembly, part number 1J770-50605, Kubota catalog description RAIL,ASSY. This is the high pressure accumulator rail for Kubota’s V2607-CR common rail diesel: it holds fuel at injection pressure between the Denso HP3 type supply pump and the injectors, and it appears as catalog section 548000 COMMON RAIL in the Kubota parts books. We verified 1J770-50605 as the current genuine number on the OEM diagrams for both the KX057-4 excavator (engine designation V2607-CR-E4-BH1/2) and the SSV65 skid steer. Kubota supplies it as a complete rail assembly with its rail mounted pressure hardware; the injection pipes, hollow screw and pipe stay shown on the same diagram are separate part numbers.

Valley Fuel Injection & Turbo is an authorized Kubota dealer and a diesel fuel injection specialty shop in Woodland, California. We are not a box shipper: we handle common rail system repair on the bench every week, we supply the full genuine Kubota engine parts picture around this rail, and we verify the part against your engine serial number before anything ships.

Application & Fitment

Confirmed applications for 1J770-50605, taken from Kubota OEM parts diagrams:

• Kubota V2607-CR-E4: KX057-4 compact excavator (diagram designation V2607-CR-E4-BH1/2)
• Kubota V2607-CR-TE4: SSV65 skid steer loader; the SVL65-2 compact track loader runs the same engine and its Kubota catalog carries the same 548000 Common Rail assembly
• Kubota V3307-CR-TE4: the V3307-CR shares this rail assembly with the V2607-CR

Dealer and aftermarket listings for this rail and its direct predecessors also reference the U55-4 and U55-5 excavators, the R530 series wheel loaders and the SVL75-2C, which is consistent with the shared V2607/V3307 common rail platform, but we have not verified those machines against an OEM diagram ourselves. If your machine is not listed above, do not guess: give us the engine model and serial number and we will confirm the exact current Kubota number for your unit.

One caution from our parts counter: do not confuse this rail with the 1J574-506xx or 1J508-506xx rail assemblies. Those fit the larger V3800 engine used in M series tractors and SVL90-2/SVL95-2 track loaders. The prefixes look similar; the rails are not interchangeable.

Cross-Reference Part Numbers

• Kubota supersession chain: 1J770-50600, 1J770-50603 and 1J770-50604 are all replaced by the current 1J770-50605. If the tag on your old rail shows any of those numbers, this is the correct genuine replacement.
• Caterpillar 436-1092: cross for the earlier 1J770-50600 / 1J770-50603 rail on the CAT C3.3B, the Caterpillar build of the Kubota V3307-CR.

Denso reference numbers for this rail circulate on aftermarket listings, but we have not verified them against Denso literature, so we do not publish them. Read us the numbers on your old rail and we will cross them properly.

Frequently Asked Questions

Does 1J770-50605 replace 1J770-50600, 1J770-50603 and 1J770-50604?

Yes. Kubota has superseded that entire chain to 1J770-50605, so the current number is the correct genuine replacement for all of the earlier rail numbers on these engines.

How do I make sure this rail fits my machine?

Have your engine model and engine serial number ready when you call. The V2607-CR and V3307-CR share this assembly, but Kubota fuel system parts can change by serial range, so we confirm the current number for your exact unit before we quote. That is standard procedure on every genuine Kubota fuel system part we sell.

My supply pump failed. Should the rail be replaced at the same time?

Often, yes. A failing supply pump can push metal debris downstream through the rail, injection pipes and injectors, and a contaminated rail will take out new components. We can advise on cleaning versus replacement, test your injectors through our mail-in rebuild service, and quote the related genuine parts for this system in one call, including the 1J770-50504 supply pump, the 1J500-50550 SCV kit and serial-correct injectors.

Why do I see this part cheaper online?
Short answer: it is usually not the same part — and it takes the fuel system with it. Read why ↓

Search any OE number and eBay, Amazon and a dozen storefronts will show it well under dealer cost, sold by outfits with no name, no address and no phone number. We lose business to those listings every week — and we see a lot of them come back through our shop. Here is what is actually different.

• The part number proves nothing on its own. Counterfeit injectors and pumps are stamped with the same OE numbers as the real thing, in housings cast to look identical. The number in the listing title tells you what the seller claims it is, not what came off an OE line.
• “Remanufactured” is not a regulated word. A genuine reman unit is stripped to bare components, has its wear parts replaced — nozzle, plunger and barrel, solenoid, seals — and is then run on a calibration bench until it meets the original flow and response spec. A cheap one is very often cleaned, resealed, painted and shipped. Both get called remanufactured.
• No full teardown, so no idea what is worn. A proper rebuild means the unit comes apart completely and every part gets inspected and measured against spec — not just the ones that are obviously bad. Skip the teardown and you are reusing worn internals inside a freshly painted housing. It will run on the truck. It will not last.
• No factory-spec bench load testing. A unit is not finished until it has been run under load on a test bench and made its numbers across the range, not just at one easy point. That bench time is most of what you are paying for. Sellers working on price cut it first, because nobody can see it in a photo.
• The warranty has to be honored by someone. Everything we remanufacture in house carries a one-year warranty, with 30 days on electrical components. Parts we supply as an authorized dealer carry the manufacturer’s own warranty. Either way you call us, a real shop in California, and we sort it out. A marketplace warranty usually means shipping the part overseas at your own cost and hoping for a reply.
• No core program. We credit your rebuildable core back in full. Discount sellers generally will not take one, so the gap narrows the moment you account for the core you are now stuck holding.
• Rail-side failures contaminate everything downstream. A rail or sensor that was never validated can strand the truck or send debris through the injectors. On a common rail system, the cheap part is rarely the expensive mistake — the fuel system it takes with it is.

We are an authorized dealer and a working fuel-injection shop — we have been rebuilding and testing this hardware in Woodland since 1993, and the people who answer the phone are the people who run the benches. Not sure this is the right part for your engine? Call us with your serial number before you order and we will confirm it. Send your rebuildable core back and the core charge is refunded. And if a price somewhere else looks too good, call 530-668-0818 and we will tell you straight whether it is a deal or a problem.

Why Buy From Valley Fuel Injection

Valley Fuel Injection & Turbo has specialized in diesel fuel injection since 1993 and is an authorized Kubota dealer. That combination matters on common rail work: we sell the genuine part and we also diagnose and repair these systems every day in our fuel injection shop. We check supersessions and serial breaks before shipping, we can package the rail with the matching Kubota pump, injectors and sensors, and if your symptoms point to diagnosis rather than parts, we will tell you that straight.

Pricing & Availability

This genuine Kubota rail assembly is sold by phone so fitment gets verified on every order. Call 530-668-0818 or contact us online for current pricing and availability. Please have your engine model and engine serial number ready and we will confirm 1J770-50605 is the correct current number for your machine before we quote it.