PROX Piston Kit is built to bring your 85cc 2-stroke back to strong, consistent running with an OEM-replacement level fit and finish. Manufactured in Japan and engineered to meet or exceed OEM specifications, it’s an ideal choice when you want dependable performance after wear, loss of compression, or during a scheduled top-end refresh. The piston is cast from a high-silicon-content aluminum alloy and then CNC-machined to extremely close tolerances, helping ensure smooth operation, accurate clearances, and reliable sealing.
By replacing the key wear components in one matched kit, you reduce guesswork during installation and get your engine ready for hard riding again—whether that’s motocross training, racing, or regular track sessions.
Key features:
✅ Japan-made and designed as an OEM replacement
✅ High-silicon aluminum alloy construction, CNC-machined to tight tolerances
✅ Complete kit with piston, ring set, wrist pin and circlips
Benefits of use:
🔹 Restores compression and throttle response for more consistent power delivery
🔹 Reliable fitment and tolerances help improve durability and reduce rebuild risk
🔹 One-box solution saves time—everything essential for the piston swap is included
Technical specifications (if needed):
📌 Displacement: 85 cc
📌 Engine type: 2-Stroke
📌 Bore size: 48.50 mm
📌 Piston size: 48.45 mm (Standard Size A)
📌 Compression ratio: Standard
📌 Material: Aluminum alloy
📌 Skirt coating: Non-coated
Why choose this product/service?
⭐ OEM-replacement quality from PROX with Japan manufacturing standards
⭐ Precisely machined components designed to meet or exceed OEM specs
⭐ Complete kit content supports a faster, cleaner top-end rebuild
