4689M07450 Wiseco .060 Piston Kit 74.50 mm 10.5:1 for Yamaha TTR250 1999-2006

Piston Kit for Yamaha TTR250

This Wiseco .060 overbore piston kit, part number 4689M07450, measures 74.50 mm and delivers a 10.5:1 compression ratio, giving your Yamaha TTR250 top end a complete rebuild solution.

Overview

This Wiseco piston kit is a .060 overbore replacement for the Yamaha TTR250, supplying a 74.50 mm forged piston with a 10.5:1 compression ratio. It is made for riders doing a top-end rebuild or a bore-out after cylinder wear, and it pairs with the corresponding overbore gasket set. This piston kit for Yamaha TTR250 restores compression and reliable running for trail and off-road riding.

Built For Performance

• Forged piston construction for added strength under load
• 74.50 mm bore size, .060 inch over stock
• 10.5:1 compression ratio for strong combustion pressure
• Wiseco part number 4689M07450 for precise cross-referencing
• Includes piston, rings, wrist pin, and circlips as supplied

Fits These Machines

• for Yamaha TTR250 1999
• for Yamaha TTR250 2000
• for Yamaha TTR250 2001
• for Yamaha TTR250 2002
• for Yamaha TTR250 2003
• for Yamaha TTR250 2004
• for Yamaha TTR250 2005
• for Yamaha TTR250 2006

On-The-Job Use

• Top-end rebuilds after piston or ring wear
• Cylinder overbore service and honing projects
• Trail and enduro riding where compression matters
• Restoring a tired Yamaha TTR250 engine

Specs At A Glance

Good To Know

Q: Does this kit require cylinder boring? A: Yes, a .060 overbore piston needs the cylinder machined to 74.50 mm before installation. Always check piston-to-wall clearance during assembly.

Q: Will I need new gaskets? A: Yes, fit a matching overbore top-end gasket set when you install this piston kit. Reusing old gaskets can cause leaks or compression loss.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.