Complete engine from a 2023 KX250 Should fit all 2021-2024 KX250 and KX250X’s. Brand new crankshaft, CNC machined head with copper beryllium seats and fresh valve job, Complete pro circuit engine performance ($4200) package including; JE High compression piston, Del West Valves, Titanium valve springs, Pro Circuit Camshafts, Pro circuit water pump and cover, New cam chain. Comes paired with a Pro Circuit tuned ECU. This engine was built for racing at the highest level. 0 hours since rebuild. See below for the pro circuit engine kit information: High-Compression Piston Kit Manufactured by JE Pistons to our exact specifications using the most advanced technologies available, our Pro Circuit High-Compression Piston Kit for the 2023-2024 KX250 provides a significant boost in low-end torque and high RPM performance. Camshaft Our newest camshaft design for the '23-24 KX250 has been designed for superior performance over the OEM cam by optimizing the valve lift profile. Used with our Pro Circuit Valve Springs will ensure a valve train free of dynamic bounce. Valve Spring Kit: The Pro Circuit Valve Spring Kit allows your motor to run at higher rpm's, and with more aggressive cam profiles without the loss of valve control. Titanium Exhaust Valves: Pro Circuit's Titanium Exhaust Valves are designed based on our race technology and manufactured to our stringent specifications by Del West, the industry leader in F-1 racing valve technology. Each exhaust valve is CNC-machined and precision ground using only titanium. Every valve is sprayed with a thermal-nitride coating to increase performance, durability and reduce normal wear. Titanium Intake Valves: Pro Circuit's Titanium Intake Valves are designed based on our race technology and manufactured to our stringent specifications by Del West, the industry leader in F-1 racing valve technology. Each intake valve is CNC-machined and precision ground using only titanium. Every valve is sprayed with a thermal-nitride coating to increase performance, durability and reduce normal wear.