Speed four charging problems

mr jamez · World Chat Champion Joined: 04 Aug 2003 Karma :

My S4 wouldn't start the other week, put a new battery in and thought it had solved it. A few days later the same problem as its not charging. I've just been charging it up with the optimate whilst I'm at work. Its putting out 12v ish so enough to run the bike.

I just had a look and found the connector to the alternator is melted and the wires on the loom side are all charred, one is broken off. I'm pretty certain that this wasn't caused by the wire melting on the engine or anything. I reconnected the broken wire but it still is only charging at 12v.

What is the most likely thing that has caused this? regulator? I guess I'll be needing a new alternator as well. Not sure what the best course of action is, I don't want to repair the loom only to have it get ruined again!
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NSR 125F > BROS 400 > NC30 > BROS 400 > Trumpet S4 > '97 VFR 750

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

My guess would be that it'll be either a mechanical failure of the wire or salty water in the connector causing corrosion. Either will cause the joint to heat up and break. Repairing the loom will probably do the job, you may be able to salvage the old connector depending on how badly damaged it is.

It's possible your regulator is knackered, but they tend to fail in the opposite way (i.e. stop regulating entirely!). You'll really need the loom fixed to find that out, though. Can't see why you would need a new alternator, unless it's clearly damaged.

f.

mr jamez · World Chat Champion Joined: 04 Aug 2003 Karma :

Well I've now repaired the loom and it hasn't fixed the problem. I've got my multimeter on the alternator wires. Two read 3.5V and the one where the wire melted is reading 0V.

Guess its time to get it out of the bike, is it possible to get them repaired?
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NSR 125F > BROS 400 > NC30 > BROS 400 > Trumpet S4 > '97 VFR 750

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Alternator wires should give you an AC reading, not DC. You are interested in the AC reading over pairs of the alternator wires (if you have a listing for an appropriate value). I would expect upwards of 40Vac.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

mr jamez · World Chat Champion Joined: 04 Aug 2003 Karma :

See this is the problem, I have no idea how to test it Laughing

I'll look for a guide and see if its possible. I've got a maual on CD but it has no details on fault finding for this problem.

If not I'm just going to send it to:

https://www.westcountrywindings.co.uk/services.htm
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NSR 125F > BROS 400 > NC30 > BROS 400 > Trumpet S4 > '97 VFR 750