Swing is the most repeated motion on an excavator — on a mass-excavation site the SK200-8 swings, brakes and swings again thousands of times a day. That duty makes the swing circuit one of the highest-wear systems on the machine, and swing parts are among the most frequently quoted at Guangzhou Shenyue Machinery Technology Co., Ltd. The questions are always the same: which motor does my machine take, do I need the reduction gear too, and how do I know which of the numbers on offer actually fits? This guide answers them with verified references.
The verified numbers: M5X130 class on the SK200-8 / SK210-8
The swing motor on the SK200-8 / SK210-8 is the M5X130 class, quoted under three assembly references that appear across supply channels:
| Reference | How it is quoted |
|---|---|
| YN15V00077F1 | Swing motor assembly, M5X130 class |
| YN15V00055F1 | Alternative assembly reference, same application |
| YN15V00035F1 | Alternative assembly reference, same application |
All three are verified against live stock records, and all three are confirmed against your machine's nameplate and serial number before quotation. The distinction matters because swing motors look alike across the Kobelco range: the SK330-8 class steps up to the M5X180 class under LC15V00022F1, and fitting a lower-class motor — or a motor paired with the wrong reduction ratio — costs swing performance and, in bad cases, the reduction gear behind it. Class, suffix and build all travel with the nameplate, not with the model name.
Motor and reduction: two assemblies, two decisions
A swing drive is two assemblies bolted together: the hydraulic motor on top, which converts oil flow to rotation, and the swing reduction (swing gearbox) below it, which multiplies torque and carries the pinion engaging the swing bearing. They wear differently and are ordered separately:
- The motor fails hydraulically. Symptoms: swing drift under load, slow acceleration and deceleration, swing motor case drain running hot or carrying metal. The motor is replaced or rebuilt and the reduction stays — if its oil is clean and the pinion is sound.
- The reduction fails mechanically. Symptoms: metallic noise or clunk on swing reversal, gear oil level dropping with no external leak (oil escaping into the motor housing is a classic sign), pinion tooth wear found at inspection. The recorded swing reduction assembly references for the SK200-8 / SK210-8 class are YN32W00025F1 / YN32W00022F2 / YN32W00019F1, confirmed per machine build before ordering.
The practical rule: when one assembly fails, open the other's oil check plug before ordering. Gear oil in the motor housing means the reduction's seals have passed — replace or reseal both sides of the joint, or the new assembly inherits the old one's problem within weeks.
Replacement points that decide whether the job lasts
- Match the assembly number, not the model name. An SK200-8 serial from one build period may carry a different F-suffix revision than another. The nameplate on the old motor or reduction is the authority; a photograph of it is enough for Guangzhou Shenyue Machinery Technology Co., Ltd. to confirm the supersession.
- Replace the joint seals between motor and reduction. Reusing a set seal on the new joint is the most common cause of a "new swing motor" failing its oil within a month.
- Refill and bleed correctly. Both assemblies need the correct gear and case-drain oil quantities on startup; running a new reduction dry for the first ten swings does damage no warranty covers.
- Check the swing bearing and pinion engagement while the reduction is off — a scored pinion or a worn bearing will eat a new gearbox's pinion quickly, and the swing bearing is far cheaper to assess now than after the failure.
How the order should be quoted
Every quotation from Guangzhou Shenyue Machinery Technology Co., Ltd. states the grade of each item — genuine, OEM-quality or aftermarket — on separate lines, and swing motors and reductions ship with photographs taken before packing. Shenyue is an independent supplier and is not an authorized dealer or distributor of Kobelco Construction Machinery Co., Ltd.; genuine Kobelco parts are supplied through original supply channels alongside quality replacement alternatives, at prices close to agent level. For an enquiry, include the assembly number or nameplate photo, machine model and serial number, quantity and destination port — the quotation returns within 24 hours.
Guangzhou Shenyue Machinery Technology Co., Ltd. stocks swing drive parts for the full -8 range among 3,000+ part types on the shelf, with 100,000+ part numbers available to order. Compare motor classes across the range in our swing motor and reduction guide, see how the big classes step up in the SK330-8 / SK350-8 parts guide, verify the generation before ordering in the SK generations and nameplate guide, and browse the category on the hydraulic components page. For fleet stocking of swing spares, read the fleet spare-parts plan, and check any reference in the part number search. Official swing circuit data from Kobelco's official site remains the reference.
Frequently Asked Questions
What swing motor does the Kobelco SK200-8 use?
The SK200-8 / SK210-8 uses the M5X130-class swing motor, quoted under assembly references YN15V00077F1, YN15V00055F1 and YN15V00035F1. Guangzhou Shenyue Machinery Technology Co., Ltd. confirms which reference matches your machine from the nameplate photo and serial number before quoting.
Which swing reduction assembly fits the SK200-8?
The recorded swing reduction assembly references for the SK200-8 / SK210-8 class are YN32W00025F1, YN32W00022F2 and YN32W00019F1. The exact assembly must be confirmed per machine build — the nameplate on the old reduction is the authority.
Do I need to replace the swing motor and the reduction gear together?
Not automatically. Replace whichever failed — but open the other's oil check first: gear oil found in the motor housing means the joint seals have passed and both sides of the joint should be serviced, or the new assembly will be contaminated within weeks.
Is the SK200-8 swing motor the same as the SK330-8's?
No. The SK200-8 / SK210-8 uses the M5X130 class (YN15V00077F1 / YN15V00055F1 / YN15V00035F1) while the SK330-8 class steps up to the M5X180 class under LC15V00022F1. Ordering by model resemblance instead of assembly number risks the wrong class of motor.