• ProX Piston Kits (Sold each). Yamaha RD350/400/RZ350/RD350LC/RD350YPVS (all years). Piston kits include piston, rings, pin and clips. ProX pistons are manufactured in Japan and are designed to meet or exceed OEM specifications. Available sizes are 64.0mm, 64.25mm, 64.50mm, 64.75mm, 65.0mm, 65.25mm, 65.5mm. Note: Use of these pistons in air cooled RD350/400 require modification of the piston skirt. We can perform this service for you. You can purchase the piston modification service here on the site under the piston category. Choose piston size, quantity and click add to cart.
  • roX Piston Modification for Yamaha RD's. We perform the piston skirt modification and ship piston ready to install. Piston modification fees are non-refundable. Price per piston.
  • ProX Piston Ring Sets (ea) Yamaha RD350/400/RZ350/RD350LC/RD350YPVS (all years). Piston replacement ring sets for ProX pistons (sold each - enough for one piston). ProX pistons ring sets are manufactured in Japan and are designed to meet or exceed OEM specifications. Available sizes are 64.0mm,64.25mm,64.50mm,64.75mm,65.0mm,65.25mm,65.5mm. Choose ring size, quantity and click add to cart.