4TN78 4TN78T Overhaul Rebuild Kit. Compatible with Yanmar Engine John Deere JD50 50 Excavator. Package included: STD Engine Overhaul Rebuild Kit. 4 Pieces STD Cylinder Liners (Semi-finished). 4 Pieces STD Piston. 4 Sets STD Piston Rings. 4 Pieces STD Piston Pin. 4 Pairs STD Piston Clip. 1 Set STD Crankshaft / Main Bearing. 1 Set STD Connecting Con Rod Bearing. 1 Set STD Thrust Washer / Bearing.