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[Barryefi]

Looks like the regulator /rectifier is faulty.. Volts from battery with engine off were 12.3. Started it, and revved engine and it took a few seconds to slowly climb to 14.2 volts. However, letting the engine back to idle it stayed at 14.3 and even switched off and on it stayed at 14.3. Turned lights on and dropped to 12.1 then when revved up went to 14.2 but dropped back on idle.

However, one corner of the battery has melted slightly and signs of acid spitting out. So, new rectifier needed and guess it'll be our hosts UK made one.

[PeteF]

Don't be too fast to replace the rec/reg. It's supposed to go to 14.2. The battery sounds like it's toast though if it's damaged.

[Barryefi]

It's the fact it stayed at 14.2 at idle ,the battery is new and put it on when I broke down. Only rode it for 30 minutes and the fact a corner has melted says the rectifier allowed it to overcharge? It melted where a corner touches the battery cover.

[PeteF]

I see what you mean but 14.2 can't overcharge a 12v battery. If the rec/reg was duff you'd get much more than that.

[Barryefi]

Weird isn't it, I wonder if it's overcharging only intermittently? Obviously the battery got really hot,it's showing a good charge and starts the bike readily so I'm guessing it's OK. My mate said if I ride with the lights on it might be OK, which is what I used to do on the old suzuki gs bikes! Think I'll have to get that rectifier and go from there eh.

[ric]

Overcharging melted the corner of the battery where it touched the battery cover OR perhaps vibrational friction between both parts produced enough heat to cause the damage.
If the charging voltage across the battery terminals remains fairly constant with the engine revs between somewhere above tickover and the rev limiter then the REG/REC unit is functioning as intended. I've just checked mine and my own reg/rec unit also delivers 14.3volts.

[Barryefi]

That does make sense, it's the little spits of acid near that corner too. But, I was getting 14.2 at idle constantly until I turned lights on. I'm just a bit paranoid now that I'm going to break down again and kill an expensive battery. Just not sure what to do, if I get the boyer bransden powerbox plus a voltage guage I should be OK!

[Jack the Lad]

You can test a reg rect to see if it faulty, the fact that it is charging the battery isn't definitive. As I said before there are lots of tutorials on you tube for how to do it. If I remember correctly is about checking for a consistent resistance across the 3 pairs of inputs, but don't quote me on that. My r/r was kaput, so I fitted the powerbox and it charges at 14.5v. It didn't at first, which worried me and only delivered full power when I upgraded the wires and connectors in the charging circuit. Fitting the powerbox is not straightforward. It is a lot bulkier than the original. You will need to make new brackets and the supplied connectors were not the same as the bike. I wouldn't do it for the sake of it and if I did it again I might look for a more mainstream r/r upgrade.

[Barryefi]

Thank you for that,I was told it was straightforward. I'm sure there's a Japanese reg/rec that will fit. I'm going to get a voltage gauge tomorrow and see what that says when riding it. If it wasn't for this forum,I think I'd have got really annoyed with this bike,thanks again to all of you.

[Leon Novello]

If all else fails, there is always the choice of an Auto-electrician who would probably find the problem in five minutes.