Honda-SOHC
Other Stuff => Misc / Open => Topic started by: royhall on September 12, 2020, 06:35:01 PM
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How much heat does an old type selenium rectifier put out. Would it be enough to damage wiring.
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I had an original one on my bike until it fried the wires going into it, that was the only indication that it had failed as well as a flat battery of course. So I would say not a good sign if theres any sign of excessive heat there. Maybe someone with more knowledge than me will verify.
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Unlike a silicon rectifier the selenium probably suffers with age and becomes resistive, which means they generate more heat than they did when new. They should not normally get hot enough to melt plastic. I did think of making up a rectifier for my 1960's bikes with the old selenium rectifier but with 4 silicon diodes of the type used on the CB750 soldered within the plate stack CB750 SOHC style (after stripping and suitably insulating) and spraying orange, so you have a silicon rectifier in the guise of the old selenium one. Of course you could just use a cheapo 5 quid modern silicon bridge rectifier off eBay as a replacement if you are not looking for originality.
Also needs mentioning that selenium rectifiers deteriorate with age even if unused, so don't expect a NOS one to be necessarily OK.
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Thanks for that. Due to all the extra wiring on the Bomber it has got quite cramped underneath the rectifier and I am a bit concerned about the heat as I cannot easily stop the cables touching the rectifier fins. I am interested in the 5 quid silicone rectifier off eBay Ash? As it's getting pretty non standard under the seat with regulators and electronic ignition boxes I don't think a different rectifier would harm things. With the out of site stuff I am more interested in reliability than originality as the bike will get used.
Had a look on eBay and to be honest I have no idea what I'm looking at. Is it something like this the item your talking about? https://www.ebay.co.uk/itm/British-motorcycle-solid-state-rectifier-A-little-tutorial-added-for-you/223333512179?hash=item33ffb6f3f3:g:SGgAAOSwInxXOPCG (https://www.ebay.co.uk/itm/British-motorcycle-solid-state-rectifier-A-little-tutorial-added-for-you/223333512179?hash=item33ffb6f3f3:g:SGgAAOSwInxXOPCG) I have bought one of these anyway as it's only a fiver and comes with his own wiring diagram and is tested by him before it leaves. For an electrical novice like me that's a big help and well worth a fiver.
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Yes that's the type Roy ... may need a bit of a heatsink ... You could also use the later CB250K4 or G5 250/360 Silicon one
https://www.ebay.co.uk/itm/Voltage-Regulator-Rectifier-for-Honda-CB360T-31700-358-305-1975-76-BE/353190494029?_trkparms=ispr%3D1&hash=item523bcb3f4d:
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That looks interesting does that also do away with the need for a separate regulator. Any idea how it's wired in.
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That looks interesting does that also do away with the need for a separate regulator. Any idea how it's wired in.
No it doesn't but there are aftermarket ones which do .. never used one myself.. I always like to keep as standard as possible
This is a cheapo one
https://www.ebay.co.uk/i/154011801651
On the other one red is +12v , Green is 0v and the other two are the AC connections.
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Thanks Ash. I have already fitted the Honda regulator so that can stay and I will wire one of those in place of the selenium unit. It will also leave more room for the extra cables. When you say 0v I assume that is battery negative (ground).
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Thanks Ash. I have already fitted the Honda regulator so that can stay and I will wire one of those in place of the selenium unit. It will also leave more room for the extra cables. When you say 0v I assume that is battery negative (ground).
Yes battery negative ... sorry
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On this one Ash.
https://www.ebay.co.uk/itm/Vol...s=ispr%3D1&hash=item523bcb3f4d:
It definitely says many times it's a regulator/rectifier?
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On this one Ash.
https://www.ebay.co.uk/itm/Vol...s=ispr%3D1&hash=item523bcb3f4d:
It definitely says many times it's a regulator/rectifier?
Link is dead Roy :(
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Yes that's the type Roy ... may need a bit of a heatsink ... You could also use the later CB250K4 or G5 250/360 Silicon one
https://www.ebay.co.uk/itm/Voltage-Regulator-Rectifier-for-Honda-CB360T-31700-358-305-1975-76-BE/353190494029?_trkparms=ispr%3D1&hash=item523bcb3f4d:
Sorry, this is the one.
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Yes that's the type Roy ... may need a bit of a heatsink ... You could also use the later CB250K4 or G5 250/360 Silicon one
https://www.ebay.co.uk/itm/Voltage-Regulator-Rectifier-for-Honda-CB360T-31700-358-305-1975-76-BE/353190494029?_trkparms=ispr%3D1&hash=item523bcb3f4d:
Sorry, this is the one.
That just looks like a straight rectifier only Roy ... The CB250/360G5 definitely had a separate reguator.