Description
The ProX Piston Kit for Yamaha GPR800/1200 D size serves engines that require a slight oversize beyond standard A, B, or C groupings, typically after light cylinder cleanup. This small additional step helps correct minor wear or taper while keeping the bore very close to stock dimensions. It is useful when measurements fall just outside standard clearance windows but a major overbore is not yet needed.
- D size piston kit for Yamaha GPR800 and GPR1200 engines needing a minimal oversize to restore correct clearances.
- Kit includes D size piston, ring set, wrist pin, and circlips to refresh one cylinder.
- Manufactured from low expansion, low friction alloy to maintain stability from idle to high rpm use.
- CNC machined to tight tolerances for skirt profile, ring grooves, and crown geometry.
- Best suited to riders wanting to extend cylinder life while maintaining near stock displacement and behavior.
When installed in a properly bored and honed D size cylinder, this ProX kit can bring back strong compression, reduce piston slap noises, and sharpen throttle response. The ring package is configured to seat quickly and provide durable sealing, making it suitable for recreational and freeride use alike. GPR engines can feel noticeably cleaner and more eager after the rebuild.
Engine builders should confirm bore diameters and out?of?round conditions, set ring gaps to recommended figures, and verify piston to wall clearances carefully. Replace gaskets and seals, inspect crank and bearings, and ensure cooling and fuel systems are functioning correctly. With careful assembly and break in, the ProX D size GPR800/1200 piston kit can keep these popular Yamaha skis running strong for many more hours on the water.
