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Starter Motor for Yamaha YFZ450R YFZ450RSE 18P-81890-00
Starter Motor for Yamaha YFZ450R YFZ450RSE 18P-81890-00
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Product Overview
Replace a worn, weak, noisy, or failed starter motor with this 9-tooth electric starter motor, designed for select Yamaha YFZ450R and YFZ450RSE ATV applications from 2009–2020 using OEM reference number 18P-81890-00.
The starter motor helps crank the engine when the electric start button is pressed. A failing starter motor may cause slow cranking, clicking, intermittent starting, no-crank issues, grinding noise, or failure to start even when the battery is fully charged.
This replacement starter motor features a 9-tooth gear, CW rotation, ≥10500 speed rating, 49.1mm mounting hole spacing, and 60.6mm width based on supplied product data. Please compare your original starter motor’s OEM number, tooth count, rotation direction, mounting points, electrical terminal, body shape, gear position, and overall dimensions before ordering.
Product Compatibility
| Make | Model | Year Range | OEM / Reference Number | Fitment Notes |
|---|---|---|---|---|
| Yamaha | YFZ450R | 2009–2020 | 18P-81890-00 / 18P-81890-00-00 | Main fitment; confirm original starter gear and body shape |
| Yamaha | YFZ450RSE / YFZ450R Special Edition | 2009–2020 | 18P-81890-00 / 18P-81890-00-00 | Main SE fitment; verify 9-tooth gear and CW rotation |
| Yamaha | YFZ450R | Select 2021–2025 applications | 18P-81890-00 / 18P-81890-00-00 | Possible extended fitment; verify original starter before purchase |
| Yamaha | YFZ450R SE | Select 2021–2025 applications | 18P-81890-00 / 18P-81890-00-00 | Possible extended SE fitment; match by OEM number and starter body |
| Yamaha | YFZ450X | Select 2010–2011 applications | 18P-81890-00 / 18P-81890-00-00 | Possible related fitment; compare original starter carefully |
| Yamaha | YFZ450 / YFZ450R ATV Platform | Select applications | Verify original part | Fitment depends on model, year, trim, and starter motor version |
Important Fitment Note:
This starter motor is mainly for Yamaha YFZ450R / YFZ450RSE applications using OEM 18P-81890-00 / 18P-81890-00-00. It is not selected by model name alone. Earlier Yamaha YFZ450 non-R models commonly use a different starter motor reference, such as 5TG-series starters. Please confirm your original starter motor matches the listed OEM number, 9-tooth gear, CW rotation, 49.1mm mounting hole spacing, 60.6mm width, and overall shape before ordering.
Specifications
| Specification | Details |
| Product Type | Electric Starter Motor |
| Compatible Brand | Yamaha |
| Main Compatible Models | YFZ450R, YFZ450RSE |
| Main Compatible Year Range | 2009–2020 |
| Possible Extended Fitment | Select 2021–2025 YFZ450R / YFZ450R SE applications, verify before purchase |
| Engine Platform | Yamaha 450cc Sport ATV |
| Tooth Count | 9 Teeth |
| Rotation Direction | CW / Clockwise |
| Speed Rating | ≥10500, based on supplied product data |
| Mounting Hole Spacing | 49.1mm / 1.93" |
| Width | 60.6mm / 2.39" |
| Main OEM Reference | 18P-81890-00 |
| Full OEM Format | 18P-81890-00-00 |
| Compact OEM Format | 18P818900000 |
| Common Vehicle Type | ATV / Sport ATV |
| Application | Electric Starting System |
| Fitment Type | Replacement, match by OEM number, tooth count, rotation, and mounting style |
Key Features
- 9-tooth electric starter motor for select Yamaha YFZ450R and YFZ450RSE sport ATV applications
- Designed for matching 2009–2020 Yamaha YFZ450R electric starting systems
- Replaces Yamaha starter motor reference 18P-81890-00 / 18P-81890-00-00
- CW rotation design for matching Yamaha 450cc ATV starter systems
- Helps restore electric start function when the original starter motor is weak, worn, noisy, or failed
- Durable metal construction supports stable cranking performance and long service life
- Precision-built replacement style supports dependable starting performance
- Direct replacement style, but original OEM number, gear count, rotation direction, terminal type, and mounting layout must be checked before installation
OEM Cross Reference
| OEM / Reference Number | Notes |
| 18P-81890-00 | Main Yamaha YFZ450R starter motor reference |
| 18P8189000 | Compact format of 18P-81890-00 |
| 18P-81890-00-00 | Full Yamaha OEM starter motor reference |
| 18P818900000 | Compact format of 18P-81890-00-00 |
| 18P-81890-01-00 | Possible related / superseding reference on some listings; verify before purchase |
| 18P818900100 | Compact format of 18P-81890-01-00 |
Please use the OEM/reference number together with physical fitment checks. If your original starter motor has a different gear tooth count, rotation direction, shaft style, mounting hole layout, electrical terminal, body width, or mounting position, this part may not fit.
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Fitment FAQ
Will this part fit my specific model and year?
This starter motor is designed for select Yamaha YFZ450R and YFZ450RSE ATV applications from 2009–2020 when the original starter matches OEM 18P-81890-00 or 18P-81890-00-00 and the 9-tooth CW design. It may also fit select later YFZ450R / SE applications, but the original starter motor must be checked before ordering.
Do I need to match the OEM part number?
Yes, matching the OEM or reference number is strongly recommended. This starter motor replaces Yamaha 18P-81890-00 and 18P-81890-00-00. However, OEM number alone is not enough. Please also confirm the 9-tooth gear, CW rotation, 49.1mm mounting hole spacing, 60.6mm width, shaft position, body shape, and terminal style.
What models or situations does this part not fit?
This part does not fit Yamaha YFZ450 non-R, Raptor, Wolverine, Grizzly, Kodiak, Warrior, Banshee, or other Yamaha ATV models that use a different starter gear count, different rotation direction, different shaft length, different mounting holes, different terminal style, or different starter body. It is also not a replacement for the battery, starter relay, starter clutch, stator, ignition coil, ECU, or complete wiring harness.
What should I check before ordering?
Before ordering, please check your ATV’s make, model, year, trim version, original starter motor OEM number, tooth count, rotation direction, mounting hole spacing, electrical terminal, shaft position, starter body width, and available installation space. For best fitment, compare the product photos and specifications with your original starter motor before purchase.