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Online store run by Xpert Moto
Local pickup available for pre-orders only
On-site installation at our Lewisham workshop
Online store run by Xpert Moto
Local pickup available for pre-orders only
On-site installation at our Lewisham workshop
Online store run by Xpert Moto
Local pickup available for pre-orders only
On-site installation at our Lewisham workshop
Online store run by Xpert Moto
Local pickup available for pre-orders only
On-site installation at our Lewisham workshop
Call us at: 0433 880 748
Free shipping over $200 (excludes tyres and bulky items)
Need help? book@xpertmotogear.com.au
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- ➔ Engine rebuild kits (1447 products)
The Vertex Top End Rebuild Kit is designed as a direct-fit solution for restoring the top end on the Yamaha YZ125 (2022 and later). It is suited to riders and mechanics looking to return a well-used two-stroke to factory-spec performance without sourcing individual components separately.
Vertex is an Italian manufacturer with a long-standing reputation in the off-road and motocross markets for precision-engineered piston components. This kit is supplied in the D bore size (53.97 mm), matching a specific bore specification for the 2022-onward YZ125 platform.
- Designed specifically for Yamaha YZ125 2022 and later models
- Bore size 53.97 mm — D size designation
- Vertex part number V-24570D
- Precision-fit components manufactured by Vertex Italy
- Top end rebuild kit format consolidates required components into a single purchase
| Brand | Vertex |
|---|---|
| Part Number (Vertex) | V-24570D |
| SKU | VK2068D |
| Bore Size | 53.97 mm |
| Size Designation | D |
| Compatible Model | Yamaha YZ125 |
| Compatible Years | 2022 and later |
| Engine Type | Two-stroke |
- Thoroughly clean the cylinder bore and all mating surfaces before fitting any new components; debris or old gasket material will compromise the seal.
- Measure the cylinder bore with a dial bore gauge before installation to confirm the bore size matches the 53.97 mm (D) piston supplied.
- Lubricate the piston pin, pin bore, and ring grooves with fresh two-stroke engine oil during assembly.
- Verify ring end gaps against Yamaha's YZ125 service manual specifications before closing the top end.
- Torque the cylinder head fasteners in a cross pattern to the value specified in the Yamaha YZ125 workshop manual — do not guess the torque figure.
- Follow a proper two-stroke break-in procedure after assembly: typically several heat cycles with varied throttle input, avoiding sustained wide-open throttle during the first few hours of running.
- After the break-in period, re-check head fastener torque once the engine has cooled.
- Store unused or removed components in a clean, dry environment away from solvents and moisture.
- Dispose of old piston rings, circlips, and gaskets responsibly — never reuse circlips once they have been removed.
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