PROX Piston Kit (Standard Size B) is a Japan-made OEM replacement designed to restore reliable compression and performance. Cast from high-silicon aluminum alloy and CNC-machined to extremely tight tolerances for consistent fit.
The PROX Piston Kit is a high-quality, Japan-made OEM replacement built to bring your engine back to strong, consistent performance. Using a high-silicon-content aluminum alloy and precision CNC machining, it delivers an accurate fit and dependable operation—ideal when you’re refreshing a worn top end or rebuilding for reliability.
By replacing key wear components in one matched kit, you reduce guesswork during installation and help ensure proper sealing and compression, so your bike starts easier, runs cleaner and maintains power more consistently.
