Old Suzuki GT380 charging problems

[Alan Moreton]

Afternoon all.
Once again, I wonder if I could ask the collective might of the forum to suggest what might be causing the issues I am experiencing on my rebuilt GT380 triple.  I know its not a 14 but I know many of you have such a vast experience across all types of bikes.

My bike was rebuilt 2 years ago using an Electrex Regulator / Rectifier and new battery in the electrical system. (Plus electronic pointless ignition and speedo / rpm gauge).  Up until a week or so ago everything was fine, but the last time out, I operated the indicators and the engine died.  The engine restarted once the indicators were switched off.  It did the same if you switched on the lights.  Once home I put a volt meter across the battery with the engine running and discovered there was no charging occurring.  The indicators aren't flashing and usually the engine stopped if they were operated.  The horn was pretty weak.  I charged the battery and it seems to be holding charge, but there is still no charge reaching the battery.  I removed the generator and found the brushes were pretty worn.  At £147 each I thought I'd try a second hand generator which I had that had almost new brushes.  The fault is exactly the same.  I can't really think that there is anything else in the system that could cause this fault other than the regulator rectifier.  Any body have any other thoughts?  Your ideas would - as always  - be much appreciated.  Electrikery is in my mind, a mystical art performed by wizards, that I do not understand!

Kindest regards  Chip

[gsxbarmy]

@Alan Moreton

One common problem on the GSX1400 is the earth lead breaking down and/or a bad earth - which would cause charging issues.

Have you tried cleaning the Earth cable from the battery or indeed adding an additional earth? Ref: https://gsx1400owners.org/forum/index.php?topic=4828.0

It may also be worth getting the actual battery checked by an electrical outlet that it's "good" - mate of mine recently had an issue and found that a 6 week old battery had failed.....

This thread may also help if the above is no help at all LOL https://gsx1400owners.org/forum/index.php?topic=306.0

[KiwiCol]

I'd say the rectifier is shagged.  I've had similar on an old bike, was the rectifier. 

[Irish in Oz]

Many years ago I had trouble with the charging on my GT380 after a rebuild too, it ended up being a plug connector going to recifier from memory it was under battery box, one of the pins had pushed back. I had similar problems with ignition bike would go off a cylinder especially with lights on. My RD400 does exactly the same if battery voltage is low it is worse if still running points ignition.

[Alan Moreton]

Thanks for your ideas.  I have checked the plugs and pins, but another check wouldn't go amiss.  The connections are under the side panel, so easy to get at and to see.  The solid state combined Regulator / Rectifier has extra earths fitted and I have double checked all those too. (thanks GSX Barmy)
The battery was down, but took a charge well so I think the battery is good.  But again, as suggested in other replies, I could get that checked out properly too.
I have the number of the technical department at Electrex and I shall give them a ring on Wednesday when their techie is in.  (Electrex have been very helpful both now and in the past).
I am running an electronic pointless ignition system.
As Kiwi Coll suggested in his reply, I do suspect the reg / rec but I don't really want to spend £95.00 if I don't have to!

Thanks again Guys.  I knew I could rely on you all for ideas.
Chip

[Hooli]

Put a test meter on the reg/rec then. It's just a bunch of diodes so straight forwards to test.

[Irish in Oz]

This may help.

[Alan Moreton]

Thanks Irish.

Electrex also have a very good fault diagnosis chart on their website.  At least I presume its very good.  If only I had the kit and the knowledge to use it!!    As I have said before, I'm ok with mechanical stuff, but electrical wizardry leaves me cold!

Chip.

[Irish in Oz]

Check the inner coil that is on the schematic, disconnect the blocks so you don't get feedback readings it may be about 2 ohms. Its so long I cant remember the layout in there only been playing around with Gt750 points and Boysen ignition lately.

[Alan Moreton]

Hello team.

Just an update and a thank you to everyone who offered help and advice.

I spoke to Electrex who couldn't have been any more helpful.  They suggested a couple of things similar in fact to some of the suggestions put out by the forum.  They also offered to check my regulator / rectifier. So I sent it to them. Next day they phoned to tell me what they had found.  There is a 12V feed into the unit, which had a corroded pin which they cleaned and tested the unit.  They suggested that I cleaned the corresponding plug on the bike loom.  They then sent the unit back free of charge and next day delivery - also free of charge!  What fantastic service.  They also sent a repair sheet back with test results and hand written suggestions. (I had explained that I was an electrical dunce).  This was all turned round in 4 days.  I took the opportunity to get the battery tested by the lads at Stowmarket Mototechnics, and whilst it was satisfactory, it was not as good as it could have been, so I got a replacement.  I also unplugged each socket in the wiring loom and cleaned and sprayed them all.

Once everything was fitted, she started up first kick, and the generator is working as it should be.  So all is well.  In fact it ran better today than it has for a week or two.

So thank you all once again for you going to the trouble to offer advice.  A virtual pint offered to all in the now open bar!

Chip.

[gsxbarmy]

What a great result and glad it's all sorted Chip