504380 Replacement XL1000 cast piston. +.040"

This +0.040-inch oversize replacement cast piston is designed for 1972-1985 XL1000 Sportster engines requiring a moderate overbore to restore proper cylinder sealing. Maintaining the standard 9:1 compression ratio, it delivers factory-specification performance at an affordable price compared to forged alternatives. The piston includes the wristpin and wristpin clips, with piston rings available separately. Cast construction offers predictable thermal expansion characteristics and excellent dimensional stability. Professional installation is recommended, with the technician verifying all component compatibility before assembly. Standard break-in procedures must be followed to ensure correct ring seating and the maximum service life from your rebuilt XL1000 engine.