Vertex WR101-081 Complete Engine Rebuild Kit - 1998-2021 Yamaha YZ125 / 2020-2022 YZ125X

Product Description

When it's time to restore the crisp, high-RPM scream of your 125, a basic top-end patch job won't cut it. The Vertex Complete Engine Rebuild Kit Collection delivers a premium, comprehensive "engine-in-a-box" solution to fully revitalize your machine's power plant from the deep bottom-end right back up to the top. Moto-House MX provides these high-performance packages featuring premium Vertex and Hot Rods components to ensure absolute crankcase compression, zero air leaks, and factory-fresh track reliability across multiple generations of the Yamaha YZ125.

Manufactured to strict precision tolerances, these setups completely eliminate the frustration of chasing down individual engine parts. Frontlined by a heavy-duty Hot Rods crankshaft and a world-class Vertex standard compression piston kit, every piece is engineered to handle the relentless stress of 2-stroke racing performance. Select your exact year from our comprehensive master application guide below and rebuild your machine the right way!

Top Features: VERTEX Complete 2-Stroke Engine Rebuild Kits

• Premium Brand Integration: Features a world-renowned Vertex standard compression piston kit packaged with a heavy-duty, factory-stroke Hot Rods crankshaft assembly.
• Complete Bearing Infrastructure: Includes specialized Hot Rods kits for main bearings, complete transmission bearings, counter-balancer bearings, and a dedicated water pump rebuild setup.
• Total Sealing Package: Includes a full Vertex engine gasket kit with all necessary oil seals and precision cylinder O-rings for complete top and bottom-end restoration.
• Year-Specific Grouping: Easily locate the exact manufacturer part number assigned to your model year for an absolute, zero-modification fit.

Don't let an old, worn-out crank ruin a fresh top end—verify your fitment list below, find your part number, and refresh your machine today!

Master Fitment & Part Number Selection Guide

Year Range	Vehicle Brand	Vehicle Model	Vertex Part Number
1998-2000	Yamaha	YZ125 (2-Stroke)	WR101-093
2001	Yamaha	YZ125 (2-Stroke)	WR101-125
2002-2004	Yamaha	YZ125 (2-Stroke)	WR101-094
2005-2021	Yamaha	YZ125 (2-Stroke)	WR101-081
2020-2022	Yamaha	YZ125X (Cross Country 2-Stroke)	WR101-081

Frequently Asked Questions

Q: How do I know which Vertex part number applies to my specific bike?
A: Simply use our Master Fitment Chart above. Locate your exact YZ125 model year to identify the matching Vertex part code (e.g., WR101-081 fits the 2005–2021 YZ125).

Q: Do these kits include everything for both the bottom and top end?
A: Yes, every package in this collection is a complete engine overhaul kit containing the crankshaft, main bearings, seals, transmission bearings, complete gaskets, and the piston assembly.

Q: Can these kits be used for high-level racing applications?
A: Absolutely. Vertex and Hot Rods engine components are heavily trusted for competitive race builds, offering race-ready durability and consistent performance under extreme track heat.

Expert Pro-Tip: The Yamaha YZ125 requires flawless crankcase alignment during assembly to prevent premature main bearing wear. When joining the case halves, never use the case bolts to force the engine together. Always use a proper crank puller/installer tool to smoothly seat the crankshaft into the bearings, checking that the crank spins completely free before performing final case torquing.

Recommended Pairings:

• Shop Yamaha YZ125 Engine Performance Parts & Accessories
• Browse Premium 2-Stroke Premix Oils & Transmission Fluids
• Browse All Vertex Engine Components

Stop by our local store in Montverde, FL or enjoy lightning-fast shipping across the USA.

Moto-House MX – Choice of Champions – is located in Clermont/Montverde, FL. The Best Motocross/UTV & ATV Shop in Central Florida.