1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Blowing Fuse

Discussion in 'Supersport (1974-2007)' started by Pylwagl, Apr 2, 2018.

  1. So, I switched on the ignition and pressed the starter button on my '93 900SS having inadvertently connected the battery the wrong way round (I know, I know, please don't say anything, I know i'm an idiot). The ignition fuse blew and there was that smell that toasted electrical components give off. I can see no apparent wiring defects so assume something has been cooked. Any ideas?
    TIA
    Stu
     
  2. Not the first won’t be the last - guessing you have changed fuse and tried again ?
     
  3. Yes, done that, fuse blew again. so guess the short is in a cooked component?.
     
  4. Starter relay ?
     
  5. Possibly, I'm not sure what the internals are like on our bikes but a relay is just a coil of wire which energised and magnetically pulls a contact shut. It should not be polarity sensitive unless theres something else in there. I thinks it's something else. Bypass the relay and if the engine turns over then it's is something else. I'll look at the wiring diagram...
     
  6. The starter relay is not polarity sensitive and won't mind which way round it is connected. There is usually a small diode connected across the back of the solenoid connector on the loom side to quench the back EMF generated when the starter button is released. It will definitely be toast but they are not really essential on these bikes. The starter won't have been damaged by being connected the wrong way round. It would have tried to turn backwards but the sprag clutch will not grip in that direction so the starter would just have spun harmlessly.
    I presume that the main 30A fuse at the RH side of the airbox is the one which is blowing. It should have protected the voltage regulator but may not have....
    With that fuse disconnected everything else should work but there will no charging. Try the bike with the fuse left out and check what works. If it cranks over make sure there are sparks on both cylinders as, apart from the regulator, the only components that might be damaged by reversed polarity are the ignition modules.
     
  7. The fuse that keeps blowing is the one for the ignition circuit in the fuse box up on the left of the clocks. indicators, lights, horn etc all work ok. I didn't notice a 30A fuse by the airbox, but there is a 30A fuse in the fusebox by the clocks - which is ok. is this the fuse you mean but in a different location?
     
  8. No I meant the one by the airbox. I will check the circuit and see what else can be effect that the main fuse powers.
    It looks like it sends power to the general relay and the ignition switch. When the ignition switch is turned to ON it energises the relay which then sends power to all the other fuses. They are all less than 30A and should blow before the main fuse if there is fault on their circuits, but you never know.
    Start by removing the relay and see if the fuse still blows. It shouldn't because power shouldn't be going anywhere.
    Then replace the relay and remove all the fuses, including the one at the side of the airbox. Now replace them one at a time and see what happens every time you replace a fuse.
     
  9. The fuse beside the airbox is a great big fecker inside a black plastic housing. You will find it at the RH side of the battery box it has the main battery +ve wire attached to it which splits off to the starter solenoid and the other side of the fuse connects to the voltage regulator.
     
  10. makes a change to blowing bubbles...
     
  11. 2128851E-7FAC-488A-918C-60BF283F7D03.jpeg
     
    • Funny Funny x 1
  12. ;)
    ill line em up..
     
    • Funny Funny x 1
  13. Mines on the RHS behind the headlight fairing just lower than the infill panel and mines a 1993
     
  14. My '94 750SS has the same type fuse in the same place.

    Try disconnecting the ignition units the next time you change the fuse that keeps blowing to try & narrow down what is causing that fuse to blow.
    Whatever has shorted out is now most likely scrap anyway so your unlikely to do any more damage. If there are other things you can unplug then unplug them too. Eventually you should be able to at least confirm exactly which unit is causing the fuse to blow, if nothing else.
     
  15. That's why I suggested removing all the fuses and replacing them one at a time. It will achieve the same result.
     
  16. I would find out what polarity the constantly blowing fuse is, and then test with a meter against the battery as going by the accompanying electrical burning smell, there is a chance that a wire has rapidly melted it’s installation through and is now shorting out somewhere.
    As already said, regulator could be the source of this.
     
    #16 Chris, Apr 3, 2018
    Last edited: Apr 3, 2018
  17. I'm trying to figure out what you mean by that. Fuses haven't got polarity. All the fuses on the SS are on the battery side of the load, if that's what you mean.
     
    • Agree Agree x 1
  18. A fuse can have an earth return or a live return, this would determine how you test to see if it’s shorting out or not. Used this method many times successfully over the years. This symptom after reversing leads on a non- ECU Ducati often ends this way, I just can’t remember the cause, it might even be the starter solenoid despite what has been said.
     
  19. I don't know how many times I have to post this......

    On a stock carbed Supersport; the big 30Amp fuse by the battery protects only the OEM reg/rec.

    If an aftermarket reg/rec has been fitted; say, the Electrex RR51 which has it's own internal fuse, there is a chance that the stock 30Amp fuse is defunct, unless it has been used again to supply the reg/rec.

    With the stock reg/rec, reversing the battery will have buggered it and it will also have cut power via the red/black wire to all the other bits like the general relay, which initially would have sent reverse current through to other components, so God knows what other damage has been caused.

    Likewise it will have probably done the same with an RR51 reg/rec.

    That means the 30Amp fuse in the fuse panel will keep blowing and as Chris says, there is a good chance that insulation on several sections of wiring has burned away.

    IMO the OP has got a job on his hands checking all the components and the wiring.

    AL
     
    • Like Like x 3
    • Agree Agree x 1
  20. Wow...

    Good to hear from you Al.

    You have been missed
     
    • Like Like x 2
    • Agree Agree x 1
Do Not Sell My Personal Information