IMPORTANT NOTICE: Piston components/kits are subject to Size AND Fitment Specificity; you NEED TO MEASURE YOUR CYLINDER BEFORE ORDERING. If you use the wrong size piston/piston rings, you will damage your cylinder and we will not be liable. Return will NOT be accepted.

Wiseco Big Bore Piston Kit

Part Number: 232M08550 

• These kits contain everything you need to complete your piston repair, the first time
• High-Performance ring kit and alloy pin included with each piston kit for extended life and sustained power.
• Dedicated forgings used for superior strength to weight ratio utilizing aerospace alloy.
• All Piston Kits are precision-crafted and forged in the USA

Wiseco's Piston Kits are offered for nearly every popular application in the Powersports market. These kits contain everything you need to complete your piston repair, the first time. High-quality parts are specifically chosen by us to match our forged pistons are included in this kit for easy one-stop shopping. 2-stroke kits feature our Pro-Lite pistons that are CNC machined for optimal cam shape and profile for peak HP and service life. 4-stroke kits feature a race-ready dome finish with smooth edges for improved combustion flow. Horizontal slot-pin oiling reduces friction and provides scuff resistance, along with a pressure seal groove for maximum ring seal. 4-stroke race applications feature Wiseco's Armor Glide skirt coating to provide reduced friction and noise to contribute to increased horsepower. Each piston is built from race-proven designs chosen by the top race teams in all forms of racing, including Supercross, Motocross, GNCC, Superbike, and more.

Fits: 
1975-78 Yamaha DT400 
1975-76 Yamaha MX400

Specs:

• Displacement: 400cc
• Bore-Standard: 85.00mm
• Bore-Actual: 85.50mm
• Bore-Oversize: 0.50mm
• Stroke: 70.00mm