Yamaha YS125 2017-2019 Starter Motor
Yamaha 12 V starter motor assembly for YS125 motorcycles using the 54P-H1890-02 starter family. Supplied as the complete Yamaha starter motor shown, with the 9-spline drive and original-style mounting arrangement.
What Is Supplied
- 1 Yamaha electric starter motor assembly
- 9-spline starter drive / output shaft
- Cast aluminium drive-end housing with two mounting points
- Starter motor body and rear end housing
- Insulated electrical power terminal with retaining nut
- Drive-end sealing O-ring as fitted/shown
The starter relay/solenoid, battery cables, separate starter gears and engine mounting bolts are not included unless clearly shown in the photographs.
Specification
- Brand: Unbranded
- Part type: aftermarket starter motor assembly
- Electrical system: 12 V
- Drive: 9-spline
- Approximate drive diameter for cross-checking: 8.9 mm
- Approximate exposed drive length for cross-checking: 24.6 mm
- Mounting: twin unthreaded mounting holes, approximately 6.8 mm
Brand: Unbranded aftermarket replacement. Yamaha names and OE numbers are used only to identify compatible applications and are not the manufacturer part number of the item supplied.
Yamaha OE References
- 54P-H1890-02 - original Yamaha starter motor assembly reference
- 54P-H1890-04 - Yamaha superseding replacement for 54P-H1890-02
Compatible OE / Interchange Reference Family
- Yamaha: B7A-H1890-00
- Yamaha: BW5-H1890-00
- Yamaha: 54S-H1890-03
- Yamaha: 2SB-H1800-10
Manufacturer / Aftermarket Cross References
- WAI: 16068N
- Dirt Racing: 19-A1040
- Lester: 16068
- Valeo / interchange reference: JYBX-004
Cross-reference numbers are provided to help identify equivalent starter specifications. This product is the Yamaha item shown and is not represented as being manufactured by the aftermarket brands listed above.
Fitment
- Yamaha YS125 - 2017
- Yamaha YS125 - 2018
- Yamaha YS125 - 2019
- Use the original OE number and starter shape to confirm fitment
Important Compatibility Check
Yamaha used different starter motors across closely related model years and markets. Before ordering, compare the original part number and starter with the photographs. Check the 9-spline drive shaft, mounting-lug positions, electrical terminal location and overall housing shape. Matching Yamaha OE number 54P-H1890-02 or its confirmed supersession 54P-H1890-04 is the safest method of confirming fitment.
Starter Fault Checks
Slow cranking or a no-crank fault can also be caused by a weak battery, poor earth connection, corroded terminals, damaged wiring, a faulty starter relay/solenoid or a fault in the starter-drive mechanism. Check the starting circuit before replacing the motor.
Installation
Disconnect the battery before removal or installation. Clean the mounting and electrical-contact areas, inspect the sealing O-ring and wiring, ensure the starter seats squarely in the crankcase and tighten all fasteners to Yamaha workshop specifications.