GB500 overcharging battery...

[sammcj]

Hi All,

I have a 1986 Honda GB500, In the last year I've had two new batterys die on me.

After just having the second battery die I cannot replace it under warranty so I want to make sure I fix it this time before buying a new one!

I've heard posts about 'rectifiers' mentioned on other forums and was looking for a bit of advice for someone trying to fix the old beast on the cheap ASAP!

Where do I start?


Battery: 12N12A-4A-1 12V 12Ah

[Kinje]

Yeah it could be a regulator/rectifier problem. Honda don't make very good ones- though I'm not sure how far back that goes.

I've cooked mine ('06 CBR600RR) and the battery started getting either no charge or massively overcharged. The symptoms were that the bike sometimes started and sometimes didn't. It would start fine with a push start and run quite happily, but it was a lottery whether it would start again after stopping, even just for a few mins.

I got it and the battery replaced by the bike shop. Got an aftermarket reg/rec and hopefully it will keep running sweet.

[vifferman]

It's almost certainly a defective R/R - either the regulation or rectification side could be bad.

Yeah it could be a regulator/rectifier problem. Honda don't make very good ones- though I'm not sure how far back that goes.

Honda don't actually make any! They're not in the electrical/electronics business. Come to that, many of their "genuine" parts are made by other companies or family businesses under licence to Honda.
The R/Rs are made by Shindengen, who have made good models for years - Honda just chose not to buy and fit those, opting instead for smaller models they could fit under bodywork. Post 2001 or thereabouts they're mostly pretty good.
So - buy an R/R anywhere, but make sure it isn't "genuine" Honda, as it will just be a Shindengen with a huge markup. They're around $300 - $350, maybe less for a smaller model.

[sammcj]

OK thanks for your help guys.
I'm on the hunt for one now!

Cheers.

[Kinje]

Honda don't actually make any! They're not in the electrical/electronics business.

Ah that explains a bit

[sammcj]

Hey,

Could it be a Shindengen CF586(click for image)?

There is one of these under the seat.

[vifferman]

Yeah, that's the R/R. There's a slight chance that it's not why your batteries are getting cooked, but unlikely: the stator can't increase its output, and even if it did, the R/R should control it if it's working.

The easy thing to do is replace it with one the same, then it's "plug'n'play", but if you can't get one, it's not hard to change the plugs and/or wiring to fit.
I've replaced two now, on two different bikes (VFR750 and VTR1000). With the first one, I ripped out all the wiring right back to the stator, and relocated the new R/R where the horn normally goes, and wired the R/R direct to the battery with heavier wiring (normally goes through the starter relay).
The VTR's one was (like the VFR) a bigger one, and I left most of the wiring intact, but installed the R/R under the frame, as it wouldn't fit under the cowl, which is a stupid place anyway. Bike R/Rs dissipate excess current via big resistors and the heat created goes through the body of the R/R and into the frame. Newer ones have fins, which helps dissipate heat. Honda must've decided R/Rs were ugly, and started hiding them under bodywork, which helps shorten their life and makes them less effective as they get too hot.
So - if you can't get a replacement Eggs Zachary the same as the old one, and it won't fit where the old one goes, don't fret - just find a New! Improved! better place for it.

[sammcj]

Yeah, that's the R/R.
The easy thing to do is replace it with one the same, then it's "plug'n'play", but if you can't get one, it's not hard to change the plugs and/or wiring to fit.

Sweet, Well I've emailed a couple of shops around NZ to see what they've got, one place quoted 150+sh for a second hand one, but im sure it's not worth that much.

Thanks again for your help.

Merry Christmas.

[vifferman]

...one place quoted 150+sh for a second hand one, but im sure it's not worth that much..

That's not a bargain. The thing is, with a secondhand one, they WON'T give you any guarantee it will work, and if it does, there's no guarantee it won't crap out after a few minutes' use. It might last 10 years, or 10 seconds.
Even if you buy a brand new "Honda" one and the dealer fits it, they won't necessarily provide you with any guarantees.

New is best, but cheap is good - just be aware that it could be a dud, or could be near the end of its life.

[sammcj]

God damn it.
I think they sent the wrong part.
GRR. (see attached)

[xwhatsit]

The little black box is a CDI -- is that what you pulled off the bike? It's unrelated to the charging system. The finned thing is a regulator/rectifier, which is what you want.

[sammcj]

I just made myself look like an idiot didn't I!
I cant see anything like what was sent on the bike, I'll have to rip off the tank today and have a look!

Thanks

[sammcj]

Found it under the tank,
It fit perfectly.
Thanks for your help, sorry for my ignorance.

[JMemonic]

If you want and can sort out a time I am happy to check the charging voltage, it takes all of about 4 minutes.

[xwhatsit]

Found it under the tank,
It fit perfectly.
Thanks for your help, sorry for my ignorance.

Haha, there's lots of confusing boxes with wires sticking out of them on my (even older and more primitive) Honda single. At least I've got a workshop manual.

Hope the new reg/rec solves your problem. Seems weird that particular reg/rec would fail, that type of Shindengen (is it a SH232?) with all the big fins is normally very reliable, not like the later ones Honda used, which look more like your CDI and tend to overheat and fail.