Regulator Question

[t-jacobs]

I have a 64 FLH with a 6 volt system. Can someone tell me which is the correct regulator for my bike. The parts book lists two ( 74500-58A Current And Voltage Regulator with fittings standard generator ) or ( 74510-47A Voltage Regulator only standard generator ) Thanks in advance for any help and info.

[Rubone]

-47A unless it is police.
Robbie

[t-jacobs]

Not Police. What is the reason for 47A?

[Rubone]

The -47 regulator was first used on the 125 lightweight. It is a two part regulator with a cut-out and voltage regulating capabilities. It was superseded by the -47A in the early '50s. It was standard on all K-Model and early Sportster systems and was adopted on Big Twins in '58. It allowed better control of the output and was suited to the new two brush Big Twin generator that replaced the earlier three brush/cutout only system. The three part regulators (large rectangular) were used on police units with high output generators and heavy loads. The -47 and -47 A are square. On your '64 it mounts on a bracket bolted to the rear motor mount bolts and is sitting upright on the right side.
Robbie