Description
The ProX Piston Kit for Yamaha GP1300R 83.90 mm A size is a standard bore replacement aimed at cylinders measuring in the tighter end of Yamaha?s specification range. The GP1300R is a high output fuel?injected two stroke, so accurate piston sizing and ring control are critical for clean running and reliable power. This kit is designed to retain stock displacement and compression while refreshing worn top end components.
- 83.90 mm A size piston kit specifically for Yamaha GP1300R applications that gauge in the small side of OEM bore tolerance.
- Includes piston, ring set, wrist pin, and circlips to replace all major piston group parts on one cylinder.
- Low expansion, low friction alloy supports stable clearances under the heat and load of performance PWC use.
- CNC machined crown and skirt geometry promote efficient combustion and smooth operation with the stock EFI system.
- Ideal for riders wanting OEM style throttle response and longevity after a top end refresh.
In a lightly honed A?class cylinder, this ProX piston can restore strong compression, crisp off?idle response, and solid pull through the mid range and top end. The ring package is tailored for quick seating and reliable sealing in high rpm operation, helping reduce exhaust smoke and maintain fuel efficiency. It pairs well with stock or mildly modified exhaust and intake setups.
Builders should accurately measure cylinder diameter and taper, verify that A sizing is appropriate, and check ring gaps and piston to wall clearances carefully. Fresh gaskets, properly torqued fasteners, and clean cooling passages help protect the renewed top end. With proper tuning and a careful break in period, the ProX 83.90 mm A size GP1300R piston kit can deliver many more hours of dependable performance on the water.
