Genuine Hepolite piston rings are designed for specific applications and are manufactured to exacting standards for precise fitment. This set of BSA A65 piston rings is designed for fitment to all model years of the 650cc unit-construction twin-cylinder models.
This piston ring set is specific to the 650cc unit-construction BSA A65 models in the 75mm standard bore condition. The top compression ring features PVD chromium nitriding on the ring face. The lower compression ring is coated with a black phosphate, and the 2-piece oil control ring uses an expander spring, providing a superior radial distribution of pressure across the cylinder bore. Made in the UK.
The piston rings form a seal during compression and promote oil lubrication of the cylinder bore walls. They must be accurately sized to fit in the piston ring grooves with clearance. The Hepolite piston rings are an excellent complement to the JCC/Emgo piston sets we offer.
Ring end gaps must be checked and adjusted, if necessary, prior to fitment to the pistons. Care must be taken when handling piston rings, as they are brittle and can be broken if mishandled, especially during fitment to the pistons. Suggested ring end gaps are .004″-.006″ per inch of bore for compression rings. End gap for the oil control ring is not as critical as the expander spring creates the even tension. The installation of the expander spring must be such that the gap of the spring is 180 degrees apart from the gap in the oil control ring.
Available sizes include: Standard, +.020, +.040, +.060 and +.080. Select your desired size from the drop-down menu.