ESR310 was designed as a high quality replacement regulator for the Yamaha XS750, XS850 triples and the XS1100 big four cylinders from the late 70’s to early ’80s.We installed our modern field control circuitry into a dedicated heat sink and outfitted ESR310 with quality wiring and connectors that plug right into the stock wiring harness. This ESR310 will give you a much more stable battery charging voltage across the RPM range and the modern electronics internally run much cooler than the OEM units.ESR310 comes with a full one year warranty.

XS750 (76-83)
XS850 (80-81)
XS1100 (78-81)