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Solved Bizarre faulty charging issue Suzuki GS500F 2005

Discussion in 'Technical and Troubleshooting Torque' started by Ghostmonger, Aug 27, 2016.

  1. Hi Netrider,

    I'm hoping someone with experience especially in electrical may be able to help me troubleshoot an issue with my bike.

    It's recently developed an issue where the battery is not being charged adequately and will eventually run flat. Initially I thought it was an issue with a loose wire however I checked all wiring under the seat and the rec/reg was still outputting into the system. However the output measured is only roughly 0.8v even with the engine revving ~4000RPM. The output from the alternator/stator was roughly 40-65VAC from idle to 4000-5000RPM so I just assumed it was an issue with the rec/reg, however I just bought a new one to test it and I'm still having the same issue, although the new one is showing around 1.2v instead of 0.8v.

    I'm thinking I'll need to pull off the side of the engine to check the stator but if anyone who has come across this issue can help before doing that unnecessarily it would definitely be appreciated! :p

    I've double-checked all the voltages, the alternator is doing up to 65VAC from all three pins, the diodes in the rectifier all check out, and as far as I can tell there are no short-outs, though that's still a distinct possibility at this stage.

    Bike is a Suzuki GS500 2005 model, bought second-hand a couple months ago as my first bike. It has been working fine for the first few months and a mechanic mate checked it when I first purchased it.
    NOTE: The bike was dropped right when the charging issue started so I imagine it's likely had something to do with it! However it was literally less than 5kph into soft garden soil so no sudden crashes on concrete etc. The issue has been a bit intermittent too so it may be a loose wire somewhere in the engine area. Also, when the rec/reg is hooked up, the system does show a more decent charge, around 12-12.5v when idling, however it'll drop to around 11.5-11.8v when the engine revs up to 5000rpm and will slowly increase from there, depending on whether highbeam is on or other lights. Also when I just checked it yesterday with the new rec/reg there was a contact noise in the engine while starting and something started smoking after a couple mins. I'm thinking maybe something is loose in the stator area. Any ideas?

    Hope this is plenty of info to help you sort it out. If there's another thread with the answer please link as I can't find anything. Let me know if you need any more details, I can check most things out. I want to learn so I know for the future.

  2. I'd say there's a earth leak somewhere that is pulling the overall voltage down. Charge your battery full connect it and then test the current flow from the battery with the ignition on, but engine off, google would most likely be able to tell you what a normal amount of current flow is. That way you'll know for sure if you got an earth leak or not
  3. I don't have access to a battery charger at the moment, I've been jumpstarting to test previously. Would this affect the issue of the voltage dropping when the engine revs? I was just reading gsresources page and they mentioned that if the insulation is deteriorating it'll drop like that. I'll see what I can do to check the current flow anyway.
  4. Service manual for the bike says the stator output should be more than 75VAC at 5000rpm too, which leans me toward an earthing issue in the stator. Sound likely? My multimeter seems crap for testing amps at the moment, I'll take it into Jaycar tomorrow and see what they say. Unfused is showing no results and with fused it's only working on mAmps when testing with a torch and overloading that.
  5. 2005 model? I wouldn't expect the insulation to have deteriorated too much, it may have rubbed through somewhere, but then I'd be expecting there to be blown fuses
  6. Ta, I'll run into Jaycar tomorrow then and see if I can get something sorted out to test the power draw for the bike.
    • Like Like x 1
    • Informative Informative x 1
  7. What's the best/easiest way to clean the connections? I can't find any burnt connections around the rec/reg at all, that's why I'm wondering if it's something around the stator. I've gone through all the steps in the how-to, the battery sits around 12.5v when idle and drops to 11.8v when revving (roughly), output from the stator is around 65VAC as stated so it is low. Resistance for stator is around 0.7Ohm all round so nothing suss. Brand new rec/reg so that's not the issue.
  8. Ok so I bit the bullet and opened up the stator case. Nothing looked too terrible, except there was a loose piece as you can see with the red arrow, and something on the wiring seemed a bit cracked. And I'm not sure what's the deal with the rust-coloured stuff on the magnets. I tested the current flow too, around 4.8amps, still trying to find a standard reading though.
    20160828_153055. 20160828_154642. 20160828_154003. 20160828_154009.
  9. Had a customers Suzuki king quad have weird readings such as yours ran the numbers by Suzuki they were stumped,readings varied cold to hot motor, turns out the stator had broken down in the wiring internally.
    Could see nothing just looking at it, yours does look cooked but that is only from photo , dark oil ,can't really tell.
    Replaced stator ,all good.
    Does ya head in doesn't it.
    This is where dealers just keep throwing parts at it until it works and then old mate gets a reaming with the bill.
  10. I reckon, it's a frickin' pain trying to narrow it down with the numbers like these. A mate is sending up a spare stator now so we'll see if it makes a difference later this week. I initially thought it was cooked too, but the wiring itself looks ok, just dark oil and insulation. Looking closer the insulation seems to have bubbled and cracked in a couple of places though so I'm guessing it might be shorting/leaking there.

    Thanks for the help guys.
  11. My guess would be a dodgy stator, especially seeing as you've replaced the rec/reg. You don't say what the voltage measures at rpms above 5,000, just that it starts to increase. It should be up around 13.8-14 at 5,000.
  12. Yeah I'm still waiting for the spare stator to check with. To clarify with the reg/rec: when it's not hooked up to the main system (just the stator, and testing the output directly) it's around 0.8v for the old one and 1.2v for the new one (no load). When the whole system is hooked up and I'm testing the battery directly, it's around 12.5v when idling (the battery is only roughly 11.5v by itself as it's still pretty flat), but drops to around 11.8v when revving the engine, especially up to 5000rpm. When sitting there, it'll sometimes slowly increase (11.81, 11.82 etc, very slowly) or decrease, especially when the blinkers/highbeam are on, so it's still not getting an adequate charge.

    Once I test the new stator with the system I'll update this thread with details.
    • Like Like x 1
  13. As a side note, never do all this testing with a flat battery.
    • Agree Agree x 1
  14. Best way to clean lugs and battery terminals for connections is with green scotch brite kitchen scourer pads. It's like steel wool but you don't get that metal residue that steel wool leaves behind. Heaps cleaner and will prep surfaces for a good electrical connection. Some koprcote or alluminox jointing paste is a good investment, helps prevent corrosion on battery terminals and helps to maintain a good electrical connection. I use koprcote a lot for this type of thing.
  15. If all else fails, you could always weld a v-belt pulley onto the end of the crank, mount an old car alternator on some Meccano where the airbox used to be (sorry, didn't mention you've got to lose the airbox and put dodgy pod filters on) and enjoy bullet proof charging for ever. ;)

    And before anyone's hair catches fire, yes I have seen this done, more than once (funnily enough, on old aircooled Suzukis), yes it did work and no it wasn't particularly pretty :D.
    • Like Like x 5
  16. So I tried a spare stator plus another rec/reg today. Still no change. Woop-de-doo :p
    I'll see if I can source a battery charger from someone and try testing again after, but the readings from just the stator and rec/reg were consistently low and similar to as mentioned before (50-60vAC, 0.8vDC). Maybe I'm just reading something wrong now, who knows.

    steve37, I would love to have had it charged previously, just working with what I can. The readings from just stator and rec/reg are still odd. Would having a flat battery cause the headlights to dip when revving (with the extra battery drain compared to standard load)?

    PatB, I'm beginning to like your idea more and more ;)

    I'm wracking my brains trying to think of what might be the issue now. Dodgy magnets? Some random wire somewhere in the realm of sorcery?
  17. Seen all sorts or dramas with flat/faulty batteries,even more so with crook wiring especially earth wires,
    Have had tractor lights dip while reving a few times ,turns out to be shit grounding,sometimes terminals sometimes engine and chassis ground points.
    Ya got to start all that testing shit with a known good battery .
    Ring a Suzuki man with your unplugged stator outputs and see what they recon about magnets etc.
    Had a Kawasaki mule with weak magnets,only just but enough to be the problem.
  18. Check and clean every connection in the charging circuit. The most frustrating electrical faults I've experience have resulted from connectors which have been fine at low or zero current, so they've shown Volts on the multimeter where there should be and no Ohms where there shouldn't, but which have broken down as soon as any real load was placed on them. Bastard things.
    • Like Like x 1
  19. Coincidences are rarely ever that, i.e. your charging circuit carks it at the same time you have a drop ? From memory the original batteries on these bikes were not sealed, it's not a simple issue of having lost battery acid whilst on its side ?

    Seeing as you have changed out the stator and the regulator it really only leaves the battery itself or the connecting wiring. As other have mentioned, I too would be checking terminals and connectors, especially the terminals at the main fuse/starter solenoid and both terminals of the battery. Also check for any voltage drop from the regulator positive lead to the +ve battery terminal, should be nil, as well as voltage drop from the negative pin of the regulator to the battery -ve, again you're hoping for no volts (i.e. no loss).

    Hope you find the gremlin.