Description

FIAT Kobelco SK30UR-2, SK20UR, SK50UR-2 Training Manual

Hands down, if you’re wrenching on a SK20UR, SK30UR-2, or SK50UR-2, you need a manual that tells you what the factory expects. I’ve seen too many guys guess on swing speed adjustments and end up with a machine that drifts. This is the FIAT Kobelco SK30UR-2, SK20UR, SK50UR-2 Training Manual — 77 pages of OEM training material, not some aftermarket rehash. It covers the engine, hydraulic system, electrics, and the performance test procedures that Kobelco uses to verify the machine is right before it leaves the plant. Every spec in here came from Kobelco Construction Machinery Co., Ltd., book code S6YO 00219ZE01, printed July 2002. That’s the real deal.

That’s the bottom line.

SK30UR-2, SK20UR, SK50UR-2: What This Training Manual Delivers

Each model gets its own serial number range: SK20UR from PB-00101, SK30UR-2 from PR-01501, and SK50UR-2 from YJ-02501. The manual covers all three, so you don’t need to buy separate books for each. You get the general view, specifications, and component identification for the ultra-small swing radius shovels. Weight on the SK20UR is 2,000 kg (4,409 lb) — useful when you’re calculating transport or lift capacity. Swing speed for the SK30UR-2 canopy version is 9.2 rpm (high) and 5.4 rpm (low). Travel speeds go from 3.0 km/h (1.86 mph) to 5.1 km/h (3.17 mph). All that data is on page 4 and 5 of the PDF.

Engine Section: What the 3TNE74-NYB Covers

Chapter 3 dives into the Engine. It’s a Yanmar 3TNE74-NYB — vertical, 4-cycle, water-cooled with a swirl pre-combustion chamber. Three cylinders, 74 mm bore by 78 mm stroke, displacement of 1,010 cc (61.6 cu in). Output is 11.0 kW (14.75 hp) at 2,000 rpm, max torque 60.8 N·m (44.8 ft·lb) at 1,600 rpm. Starter is 12 V × 1.0 kW, generator 12 V × 20 A. If you’re chasing a no-start or low-power complaint, this section tells you exactly what the factory expects for output and torque curves. No guesswork.

Hydraulic System: Variable Displacement Axial Piston

Chapter 5 covers the hydraulic system — variable displacement axial piston pump plus a gear pump, axial piston swing motor, and a 2-speed variable axial piston travel motor. The control valve has nine spools. Cylinders are double-acting for boom, arm, bucket, dozer, and offset. Return filter has a paper element with a 30-micron safety valve. The offset mechanism gives you 330 mm right and 805 mm left movement from the crawler side. Understanding these specs matters when you’re diagnosing weak curl or slow swing. The travel motor is a 2-speed variable axial piston motor — think of it like a Manual Transmission in a car: you have low and high range. The manual explains how the pressure and flow change between speeds.

Performance Test Procedure: What You’ll Find on Page 55

Chapter 7 is the performance test procedure. This is where you verify swing speed, travel speed, gradeability, and hydraulic pressures. You need a tachometer, pressure gauges, and a stopwatch. The manual gives you the test conditions — engine at full throttle, oil at operating temperature. For the SK30UR-2, gradeability is 30° (58% grade). If your machine won’t climb that, you’ve got a drive motor or hydraulic issue. Don’t skip this chapter. I’ve seen guys throw parts at a machine when the real problem was a misadjusted relief valve. The test procedure on page 55 tells you exactly which port to tap and what pressure to expect.

Periodical Check Maintenance: Page 66

Chapter 8 lays out the periodic checks and maintenance intervals. Oil filter, air cleaner, radiator, coolant, hydraulic tank breather — all listed with the factory recommended schedule. No more wondering “is this every 250 hours or 500?” The manual spells it out. Also covers the idler adjuster and rubber shoe condition. If you’re running these machines in a rental fleet, this chapter alone saves you from downtime. Pair this with the Kobelco SK30UR-2 Parts Catalog and you’ve got the full package.

Control Equipment: Why This Training Manual Matters

Chapter 2 covers control equipment — the monitor panel, sensors, and switches. The SK30UR-2 uses angle sensors on the arm and offset cylinders. There’s a canopy interference prevention system (Chapter 6) that keeps the cab from contacting obstacles. Understanding how the control unit reads those sensors is critical. The manual is a training text, so it explains the theory behind the logic. It won’t give you wiring pinouts — that’s in the shop manual. But it will show you how the system should behave. For larger machines, the KOBELCO SK460-8 SK480LC-8 2007 Service Training and KOBELCO SK460-8 SK480LC-8 2007 Training Manual follow a similar logic. And if you’re new to hydraulic controls, think of the control valve spools like shifting a Manual Transmission — each position changes flow path. This manual teaches you the basics so you don’t burn up a pump.

FAQ

Can I use this manual to rebuild the hydraulic pump?

No. This is a training manual, not a shop manual. Refer to the shop manual for overhaul procedures.

What serial numbers does this cover?

The manual covers SK20UR starting at PB-00101, SK30UR-2 from PR-01501, and SK50UR-2 from YJ-02501. These are the training text book code S6YO 00219ZE01 from 2002. It is intended for technicians learning the systems, not for disassembly. You’ll find theory, component identification, and performance tests. For part numbers, you need the parts catalog. For wiring diagrams and torque specs, you need the service manual. This training manual fills the gap — it tells you how the systems work together so when you open the service manual, the steps make sense.

Look, I’ve been turning wrenches since before some of you were born. A training manual like this one is what separates a parts-changer from a real diagnostician. You get the factory’s own explanation of how the hydraulics interact with the engine and electrics. That’s the kind of knowledge that keeps a machine running for 10,000 hours without a major failure. Access the Factory Manual now and put it on your tablet in the cab. You’ll thank me the first time you have to track down a swing brake problem on a SK50UR-2.