Vintage Honda Motorcycle Not Charging? Here's an Easy (Potential) Fix and Upgrade! 

That's interesting, glad to hear it fixed it! There's also obviously other issues that can cause lack of charging (stator charging coils for instance) - but the rectifier units on these older Honda's always seems to be a big culprit! One way to seperate out and check the charging coils is to check the AC voltage coming out of each of the wires, per book spec.

Glad you enjoyed it!

Travis, I'm glad that this could help out, sorry for the delay! Thank you for the support, it's much appreciated!

Nope, this is the only video made so far on it. Although, I can't say that I've personally had much issue with over-charging the batteries after swapping out to a newer regulator. That being said, I also very seldom run the 6V sealed batteries and usually stick with the OEM type. (This one the PO had installed one of the sealed units on). And, to the second point, I suppose admittedly I don't ride wide open for extended periods of time on these either. Upon searching, it does look like many of the units are touted as 'Regulator Rectifiers' with one of them specifically advertising that it regulates the voltage unlike the original Honda ones. So, I would imagine if that's the case, then those units would work as an improvement over original and should not overcharge the battery. The original 'Radio Shack' rectifier fix that was popular a few years back? Yeah, probably not.

True. The silicon rectifier has a lower voltage drop than selenium - the higher output power can cause overcharging, and battery damage is common. My 305 was chronically undercharging with selenium and overcharging with silicon. I rewired to use the higher output "lights on" dual coils all the time and added a shunt regulator that dumps excess power into a resistor. Yes it's a waste of engine power but not significant. Definitely significant improvement over the original "hope for the best" no-regulator charging system.

Thanks! I'm not sure what difference there is between the 5.4 number stamped on there and 5.5? I dont' think there'd be any, especially if they are the same Honda part number and fitment. I don't think you can buy just the rubber cover for them, and if it that has disintegrated, the recitifer is likely old and worn out anyways. As far as retaining the original look, I do see some NOS ones on Ebay for around 100 bucks or under. I thought that somebody was making upgraded versions that retained the factory look like offering improved charging, but I can't find any for the 90's. This is what I'm thinking of though, offered for the 305's: scramblercycle.com/products/honda-cb77-cb72-rectifier-31700-268-000-new-reproduction

This came in a box of extras for my CT90, but it's simliar to the one here: www.ebay.com/itm/125622573867?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=NPMxQAH_Tzu&sssrc=2047675&ssuid=j67w78AqRLq&widget_ver=artemis&media=COPY