A short-radius Kobelco is not a small machine with a short tail. The SK115SR, SK125SR and SK135SR are built to swing inside a single traffic lane and to work between walls, and that duty shapes every consumable on the machine. Buyers who treat an SR as a scaled-down SK200 tend to order wrong at both ends — too light on the undercarriage, too heavy on the hydraulic circuit. Guangzhou Shenyue Machinery Technology Co., Ltd. has been supplying parts for Kobelco machines since 2007, and this guide sets out what the SR suffix actually changes.
What short radius really changes
On a conventional excavator the counterweight overhangs the rear of the tracks. On an SR machine the upper structure is engineered so the tail stays inside the track width through the swing. That one change moves the swing centre, the weight distribution and the service access, and it changes the loads the swing bearing and swing motor see. An SR machine spends its working life swinging far more often than a conventional machine of the same size — a utility job is a hundred short swings rather than ten long ones — so swing components and swing bearing lubrication stop being an afterthought and become the wear items that decide the machine's cost per hour.
The second difference is the work envelope. SR machines are bought for road works, trenching between buried services, demolition inside a building shell and yard duties where a full-size machine cannot fit. Blade and outrigger variants are common in this class, and the attachment is switched more often than on a production machine. Every one of those factory choices is reflected in a part number somewhere.
The classes do not line up with the model number
The trap is the hydraulic and drive class sitting behind the model number. A 12 to 14 tonne SR does not automatically carry the same pump, travel motor or final drive family as a conventional machine of the same nominal weight, and the SR suffix can be followed by a further designation that changes the undercarriage or adds a blade. Treat the class as something to be confirmed from the component, never assumed from the badge.
| What you are ordering | What actually decides it | What the model name cannot tell you |
|---|---|---|
| Hydraulic pump | The pump nameplate and its family | Whether the machine carries the SR variant of that pump |
| Travel motor | The motor nameplate (Nabtesco family) | Which travel family and build the machine was assembled with |
| Swing motor and reduction | Swing nameplate plus the swing bearing number | Whether a blade or outrigger variant changed the mounting |
| Undercarriage | Track frame, roller and idler numbers | Whether the machine left the factory on the standard or the heavy frame |
| Engine consumables | The engine plate — the D04EG class on an SK125SR | Which turbocharger build the engine was built with |
The engine end of the range is easier than it looks
SR machines in this size band run a four-cylinder Kobelco and Hino family engine rather than the six-cylinder J05E and J08E units used further up the range, and the turbocharger fitted to the SK125SR is documented in our own video library under the D04EG designation. Because these are small-displacement engines working close to their limit, boost-related faults surface early: black smoke under load, a whistle that changes pitch as the engine warms, or a machine that pulls well cold and goes flat when hot. On a four-cylinder machine the air filter, the intake path and the boost pressure reading all have to be checked before the turbocharger is condemned, because a restricted filter produces the same symptom at a fraction of the cost.
Ordering SR parts without a return
Three habits keep SR orders clean. First, photograph the nameplate of the component being replaced rather than only the machine plate, because the SR suffix alone does not identify the pump or motor family. Second, keep the undercarriage and the hydraulic lines separate on one quotation, so a wrong line can be quarantined without holding up the rest of the machine. Third, check the numbers against the hydraulic families listed on our hydraulic components page before anything is confirmed. The model pages for the SK115SR, SK125SR and SK135SR set out the machines themselves.
How we supply
Guangzhou Shenyue Machinery Technology Co., Ltd. has specialised in Kobelco since 2007, with 4 warehouses over 1000 m² in Guangzhou, 3,000+ part types on the shelf and 100,000+ part numbers available to order through original supply channels. Shenyue is an independent supplier and is not an authorized dealer of Kobelco Construction Machinery Co., Ltd.; for Kobelco, Hino, Isuzu, Yanmar, Cummins, Kawasaki, Nabtesco, KYB and KPM we supply genuine parts ordered through original supply channels alongside quality replacement alternatives at prices close to agent level, and the five brands we hold formal authorization for — Mitsubishi, Garrett, TONGMYUNG, Marusan and NIKURA — are named on every quotation. Published Kobelco machine information is a useful cross-reference when an SR variant has to be pinned to a build year.
Frequently Asked Questions
Are SK115SR parts the same as SK115 parts?
Not necessarily. The SR suffix denotes a short-radius upper structure and work envelope, and the hydraulic and drive classes behind the model number have to be confirmed from the component nameplates. Order from the machine plate plus the nameplate of the part being replaced rather than from the model name alone.
Why does my short-radius Kobelco swing motor cost more than I expected?
Because SR machines swing far more often than conventional machines of the same size, the swing components and the swing bearing are worked harder, and the class behind the model number is often larger than buyers assume. Confirming the swing motor family from its nameplate is the only way to price it correctly the first time.
Do SR machines use the same engine as an SK200?
No. Machines in this band run a four-cylinder Kobelco and Hino family engine rather than the six-cylinder J05E and J08E units used in the 20-tonne class. The turbocharger for the SK125SR is documented in our video library under the D04EG designation, so engine parts must be ordered from the engine plate.
What should I send for a short-radius parts quote?
The machine plate with the full designation and serial, the hour meter reading, and a photograph of the pump, travel motor, swing motor or engine nameplate. Guangzhou Shenyue Machinery Technology Co., Ltd. confirms the class from those plates and declares every line's grade — genuine, OEM or aftermarket — before quoting.