74510-70A voltage regulator

[otis71]

I found an obsolete OEM 74510-70A voltage regulator with the chrome housing for my 74 FLH. The factory upgraded the part number to a finned aluminum one. The OEM chrome one has the black wire that goes to the battery and also a red wire with a connector on it. The schematic in the service manual only shows the black wire. The picture in an old parts book shows the extra red wire in the picture but the updated one only has the black battery wire. Any help on where the red goes or if it is needed? Thanks.

[Rubone]

Tachometer wire if I recall correctly. Been a long time since I messed with one of those set-ups.

[motorhead1]

You are correct. It is a tach wire.

[Motorman55]

Bringing this Thread back up.

I have the same regulator/rectifier on my 74 FLH. Should I attach both the red and black wires to the + battery post or should I just cap off the red one?

Thanks for any info.

[otis71]

If I recall correctly the black wire goes to the battery and the red doesn’t get used.