Fitment: For Honda GX340 390 420 Engine Go Kart Mini Bike.4.450" center to center for a 1.416" crank pin and a .788" wrist bore.Note that the minimum clearance between piston and head is 0.030". Package Includes: 1*Connecting Rod,2*Bearings. Strength improvement: Use more durable materials to improve bolt strength and avoid bolt breakage. Bolts can reach 170 inches/lb.Uses 5/16" rod bolts.Use an inch pound torque wrench with a 1/4″ 12 point socket. Installation method: The product contains a manual with detailed installation steps. Please strictly follow the manual to avoid product damage.