66.4mm Standard-Bore Piston Top-End Rebuild Kit for Yamaha YZ250 1999–2025 / YZ250X

Name: 66.4mm Standard-Bore Piston Top-End Rebuild Kit for Yamaha YZ250 1999–2025 / YZ250X
Brand: Northline Parts
SKU: NLT2S00882
Price: 809.39 USD
Availability: InStock

SKU: NLT2S00882

$809.39 In Stock

$809.39

Ships for free in 2–4 business days.

This 66.4mm standard-bore top-end kit is listed for Yamaha YZ250 two-stroke motorcycles from 1999–2025 and compatible YZ250X applications. Measure the cylinder and verify the included piston components before ordering.

Estimated delivery between

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Compatible Models

We do our best to list all compatible models. Although this may be the part you need, your exact model may not appear below.

Listed applications and configurations:

1999 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2000 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2001 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2002 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2003 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2004 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2005 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2006 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2007 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2008 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2009 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2010 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2011 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2012 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2013 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2014 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2015 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2016 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2017 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2018 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2019 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2020 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2021 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2022 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2023 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2024 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2025 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
2016 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2017 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2018 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2019 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2020 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2021 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2022 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2023 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2024 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant
2025 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant

Fitment note: Measure the cylinder with the correct tools. Standard 66.4mm nominal bore does not prove the cylinder is serviceable or that every included gasket fits each generation.

Product Overview

Top-end replacement components renew the worn piston-and-ring sealing surfaces on the 249cc two-stroke engine.

Low compression, difficult starting or piston wear can call for a top-end service, but the correct piston grade and cylinder plating condition must be established first.

Measure the cylinder with the correct tools. Standard 66.4mm nominal bore does not prove the cylinder is serviceable or that every included gasket fits each generation.

Key Features & Performance

Application: 1999-2025 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore.
Purpose: Top-end replacement components renew the worn piston-and-ring sealing surfaces on the 249cc two-stroke engine.
Identification: Match the pictured component to your original part before ordering.

Specifications

Part / assembly: 66.4mm Standard-Bore Piston Top-End Rebuild Kit
Application / size: 1999-2025 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore
Reference number(s): No independently confirmed OEM interchange number supplied
Northline Parts SKU: NLT2S00882

Replaces Part Numbers

A reliable OEM replacement number has not been established for this listing. Verify the original component markings, measurements, and configuration rather than ordering by vehicle name alone.

What Is Included

The replacement component or kit pictured in this listing. Accessories, mounting hardware, fluids, and seals are included only when specifically shown or stated.

Installation & Fitment Notes

Measure the cylinder with the correct tools. Standard 66.4mm nominal bore does not prove the cylinder is serviceable or that every included gasket fits each generation.

Inspect related components during replacement and follow the equipment manufacturer’s procedures for fastener torque, alignment, sealing, and any required calibration or fluid service. Do not assume that installation supplies or fluids are included.

Frequently Asked Questions

Is this an OEM part?

No. Unless the product listing explicitly states otherwise, this is an aftermarket replacement. The manufacturer names and OE references identify applicable equipment, not the maker of this item.

How do I check fitment?

Measure the cylinder with the correct tools. Standard 66.4mm nominal bore does not prove the cylinder is serviceable or that every included gasket fits each generation.

What if my model year appears above but the part looks different?

Do not install it based on the model year alone. Factory equipment changes by engine, build date, trim, mounting style, and option package. Match the original part number and physical connections first.

Part Summary

Part: 66.4mm Standard-Bore Piston Top-End Rebuild Kit

Applications: 1999-2025 Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore; 2016-2025 Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant

Reference Numbers: No independently confirmed OEM interchange number supplied

Purpose: Top-end replacement components renew the worn piston-and-ring sealing surfaces on the 249cc two-stroke engine.

Northline Parts SKU: NLT2S00882

Keywords: 66.4mm Standard-Bore Piston Top-End Rebuild Kit, 66.4mm Standard-Bore Piston Top-End Rebuild Kit for Yamaha YZ250 1999–2025 / YZ250X, NLT2S00882, Northline Parts, Yamaha YZ250 — 249cc 2-stroke, 66.4mm standard bore, Yamaha YZ250X — 249cc 2-stroke, 66.4mm standard bore, confirm kit variant.