Fitted from the factory, the BETA PISTON RING D67,4 (OEM 026.02.089.00.00) is Beta’s original Crankshaft/Piston/Balancer Shaft component for the RR 250 2T RACING, RR 250 2T X-PRO, X-TRAINER 250 2T (2026–2027). It keeps your Beta performing exactly as the factory intended. Replace it as part of normal maintenance or after wear. Genuine OEM ...