Description
The ProX Piston Kit for Yamaha GP800R/1200R 0.50 mm oversize is tailored for the high performance GP series twins and triples that see hard recreational and freeride use. A half millimeter overbore is ideal when cylinders show moderate wear or light scoring that standard pistons and a simple hone cannot correct. This kit lets builders clean up the bore while preserving plenty of wall thickness for future services.
- 0.50 mm oversize piston kit engineered specifically for Yamaha GP800R and GP1200R two stroke engines.
- Includes oversize piston, ring set, wrist pin, and circlips for a complete top end component group.
- Manufactured from a low expansion, low friction alloy to maintain correct running clearances under sustained high rpm.
- CNC machined skirt and crown promote stable operation and efficient combustion in aggressively ridden skis.
- Well suited for freeride, surf, and performance lake use where crisp throttle response is valued.
Installed in a properly bored and honed cylinder, this ProX kit can restore strong compression, sharpen low end punch, and improve mid range pull out of turns. The ring package is designed to seat quickly on an appropriate cross hatch pattern, helping reduce blow by and exhaust haze. When combined with correct jetting or fuel mapping and quality two stroke oil, GP800R and GP1200R engines can feel noticeably younger.
Engine builders should measure bores carefully at multiple heights and directions, set ring gaps to recommended values, and verify piston to wall clearances. Inspect crankshafts, bearings, and seals, and renew base and head gaskets as part of the rebuild. With careful assembly and a patient break in period, the ProX 0.50 mm oversize piston kit supports many more seasons of spirited Yamaha GP riding.
