Gsf 250 charging problems

[geemannz]

So I've had my gsf250 for a month and a half or so. When I got it the battery seemed pretty buggered (not starting, having to crash start etc), so I replaced it with a new one from the local motorcycle shop. Everything since has been fine except the same problems are starting to occur that caused me to replace my last battery.

I charged the battery, left it overnight, and check the voltage in the morning. Voltage was 12.8V, I then started the bike and the voltage was around 13.3V. Rode the bike to work (about 10km) checked the voltage again while the bike was off and the battery voltage was about 12.3V. Started the bike again and the voltage was again around 13.3V. I then revved the bike and the voltage immediately dropped to around 12.9V-13.0V.

This seems strange to me that the voltage would drop so sharply when revving the bike. I'm thinking problems with the charging coils (not sure what they are called on a bike, most of my mechanical/electrical experience is on cars).

Any ideas on what this could be?

[buggerit]

Sounds like its charging ok, the slight voltage drop when you rev it is probably the regulator coming into play.
I would be looking for a parasitic draw on the battery when the key is off, pre computer so imagine
there should be no draw from battery with key off if everything is functioning correctly.

[geemannz]

Sounds like its charging ok, the slight voltage drop when you rev it is probably the regulator coming into play.
I would be looking for a parasitic draw on the battery when the key is off, pre computer so imagine
there should be no draw from battery with key off if everything is functioning correctly.

Ill chuck a multimeter on it and see if there is any current draw.
The only thing that I can think of that would cause that sort of draw is the aftermarket horn one of the previous owners installed, so i'm not sure

[geemannz]

Sounds like its charging ok, the slight voltage drop when you rev it is probably the regulator coming into play.
I would be looking for a parasitic draw on the battery when the key is off, pre computer so imagine
there should be no draw from battery with key off if everything is functioning correctly.

I chucked a multimeter on the bike and was reading a parasitic draw of 0.42A when the key is turned off.
I isolated the horn wiring and still found the parasitic draw of the same current.

It doesn't seem like much, but I suppose that fact it doesn't have any computers, and its a reasonably small battery.
I'll have to get around to diagnosing that, or install a battery isolator switch. One of the two.

[buggerit]

Ill chuck a multimeter on it and see if there is any current draw.
The only thing that I can think of that would cause that sort of draw is the aftermarket horn one of the previous owners installed, so i'm not sure

I would pop the negative lead off and then see if you can get a spark between the terminal and the lead by lightly
brushing them togeather, if a good spark it could smoke your multimeter if you hook it up
in series to get an amps draw figure but if faint probably safe to do so.
one of the places you get a current loss is through your regulator/rectifier when diodes etc begin to fail.

[geemannz]

I would pop the negative lead off and then see if you can get a spark between the terminal and the lead by lightly
brushing them togeather, if a good spark it could smoke your multimeter if you hook it up
in series to get an amps draw figure but if faint probably safe to do so.
one of the places you get a current loss is through your regulator/rectifier when diodes etc begin to fail.

Bit late for that I guess lol. Thanks for the tip about the reg/rect. Ill have to check that out before I do anything.

[buggerit]

Bit late for that I guess lol. Thanks for the tip about the reg/rect. Ill have to check that out before I do anything.

half an amp is a fair bit over 24hrs, soon flatten a battery.

[geemannz]

half an amp is a fair bit over 24hrs, soon flatten a battery.

Looks like ill have something to do over the next couple of days. Cheers for your help

[F5 Dave]

Geez that's huge loss. Erm, try unplug the regulator and dash and anything else you can think of until it stops.

I'd be expecting to see 14v or thereabouts so you sound like a touch low. Maybe connected.

[jellywrestler]

one of the places you get a current loss is through your regulator/rectifier when diodes etc begin to fail. or one of the phases of your alternator has failed, as revs increase the load does so the alternator isn't able to keep up and manifests as a voltage drop.
suzukis are renowned for poor charger systems in the older days

[geemannz]

or one of the phases of your alternator has failed, as revs increase the load does so the alternator isn't able to keep up and manifests as a voltage drop.
suzukis are renowned for poor charger systems in the older days

I should be able to check that my checking continuity between the outputs yes? Assuming I can find the wires.

[F5 Dave]

3 same coloured wires come out of stator through a connector (check contacts and plug melting) heading for the Rectifier-regulator. Unplugged you should get say 50vAC or at least the same as each other. Check ideally when warm but cold might give you a bad fault ie. Sometimes the insulation breaks down and wires touch only when hot for example.

[Ginge09]

Hook up the meter with the bike off and start pulling fuses. When the 0.42amp draw goes away that’s your problem circuit. Ride to work. Unplug fuse. Plug back in to ride home.

[F5 Dave]

Or perhaps, you know, fix it. Might be important like:blink:

[geemannz]

Or perhaps, you know, fix it. Might be important like:blink:

Eh who want to actually fix problems, if a bodge fix breaks, bodge it again right?

[F5 Dave]

Now you sound like my coworkers when we have 2 or 3 planes to turn around in an hour.

I'll give you a tip, don't fly on a Friday.


Kidding:msn-wink:

[Ginge09]

Obviously fix it, but the bloke uses the bike to get to work. Not everyone has the opportunity to fix stuff when the problem immediately presents.

Pulling the fuse for the time he's at work long fingers the problem until he's got a clean shot at it. Or until the parts turn up.

[buggerit]

Hook up the meter with the bike off and start pulling fuses. When the 0.42amp draw goes away that’s your problem circuit. Ride to work. Unplug fuse. Plug back in to ride home.

The fuse box is down stream from the key so should not be any power there with the key off.
The only fuse on the battery side of the key is the main fuse which is probably hiding round the starter motor relay.
Unplug the reg/rectifier and check again with key off would be my first test.

[Ginge09]

Yeah, agree with that.

Hook the meter up at the battery to measure amps draw and start pulling fuses. The one before the key first.

Any current draw after that indicates a crook ignition switch for a start. Followed by whatever fuse is linked to the dodgy circuit.

[buggerit]

Yeah, agree with that.

Hook the meter up at the battery to measure amps draw and start pulling fuses. The one before the key first.

Any current draw after that indicates a crook ignition switch for a start. Followed by whatever fuse is linked to the dodgy circuit.

If you pull the fuse before the key the only live wire on the bike will be the cable from the battery to the starter solinoid.
A voltage check at the accessory fuse box with the key off should indicate if the key switch is functioning correctly