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Regulator / Rectifier - Honda CB350F CB400F CB500 CB550 CB750


Product Description

Battery not charging? Might be time to replace your rectifier or regulator, and why not replace them both at once with a part that will work better than the originals. This Rectifier / Regulator Combo will replace both your old rectifier and regulator. Unlike many other units, this regulator rectifier is designed to work with lead acid based battieries, including Gel batteries as well as lithium batteries. You must have a fully charged battery in perfect working order before installing a new regulator rectifier.

Dimensions: 82mm Long x 30mm tall x 80mm wide
Mounting Hole spacing - 66mm (measured center to center)

Replaces these Honda OEM part numbers: Rectifier: 31700-333-008 Regulator: 31400-300-035

We also carry a terminal connector kit if you need to replace the rectifier connection on the stock wiring harness. If the stock connector is brittle and the terminals are corroded, it's best to replace it.

Here's a very helpful SOHC forum thread on testing the charging system 

Note: The white 5 wire connector plugs into the stock wiring harness, replacing the old rectifier. The 3 male spade connectors plug in where the old regulator connected. Corroded / loose / damaged wiring is a very common cause for charging system issues, make sure all connections are clean and secure. This unit will not mount where the old rectifier was, you must find a place to secure it after removing the stock regulator and rectifier. The body of the unit does not need to be grounded.

Fits Honda:

CB350F - 1972-1974 
CB400F Super Sport - 1975-1977
CB500K - 1971-1973
CB550F Super Sport - 1975-1977
CB550K - 1974-1978 
CB750F Super Sport - 1975-1978
CB750K - 1969-1978

Designed to work with 3 phase charging systems on pre-1979 Honda SOHC4's

Product Reviews

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  1. Excellent upgrade 5 Star Review

    Posted by on 22nd Aug 2017

    Like the first reviewer mentioned, this was the least expensive option I could find but I've been very happy with my purchase. It works great on my CB350F and the wiring was plug and play. I'm now using a maintenance free AGM battery. This bike starts easier than it ever has. Highly recommend!! Thanks 4into1!

  2. Works great 5 Star Review

    Posted by on 24th May 2017

    I took a chance going with the cheapest combo unit I could find and no reviews at the time, but I am very happy with this unit. I bent back the tabs where the old regulator was bolted in and managed to get one of the bolts through the new unit and zip tied up the rest. Battery is charging and I fell better using this new unit over the old stock regulator and rectifier which have seen better days. Everything hooked right up to the stock harness and wiring, no modifications needed. Would recommend!