XR50 / CRF50 / Z50R

Honda XR50 / CRF50 / Z50R Big Bore Kits

Upgrade your Honda XR50, CRF50F, or Z50R with big bore kits from TB Parts. These classic Honda mini bikes share a common engine architecture, and TB Parts bore-up kits provide a reliable power increase with direct bolt-on fitment.

XR50 / CRF50 Big Bore Kit Options

TB Parts offers big bore kits for the Honda XR50R, CRF50F, and Z50R that increase displacement for more torque and top-end power. Kits include a bore-up cylinder, piston, rings, and gaskets. Available in multiple displacement options to suit your build goals.

Performance Cams & Engine Parts

Pair your XR50 or CRF50 big bore with a TB Parts performance camshaft for additional power gains. Also available: cam chain tensioners, valve springs, and other engine components to complete your mini bike build.