Rick’s Motorsport Electrics, Inc. offers both new and rebuilt alternators for most ND fan cooled alternators. All rebuilt alternators require a core exchange. We also offer replacement rectifiers (part# 30-501) and voltage regulators (part#30-502) on most models. PLEASE NOTE: Before replacing a 30-501or 30-502, be sure to check the OHMs reading on your rotor. A reading of 3.5 – 4.5 is required. Without sufficient resistance,failure will result and the warranty will be void.