Master fuse keeps blowing

[jonnyk5614]

So was riding last night and the master blew. Pulled all the secondaries and the master blew again as soon as I put the key in "Park". So I unplugged the tail light, key to park, same again. Ran out of fuses and things to unplug and called the AA.

Am I best to call motorcycle doctors or an auto electrician?


Sent from my iPhone using Tapatalk

[nodrog:Me]

So was riding last night and the master blew. Pulled all the secondaries and the master blew again as soon as I put the key in "Park". So I unplugged the tail light, key to park, same again. Ran out of fuses and things to unplug and called the AA.

Am I best to call motorcycle doctors or an auto electrician?


Sent from my iPhone using Tapatalk

checked the voltage at the battery?

your regulator rectifier may be fucked.

[jonnyk5614]

Hard wired phone charger works fine
And this is with the bike off


Sent from my iPhone using Tapatalk

[nodrog:Me]

I tried to help.

[Banditbandit]

OK .. go to your office, or wherever you keep such supplies. Find a paper clip ... open it out into a U-shape, and then insert each end into the place where your fuse sits.

Alternatively, take a cigarette packet, remove the inside foil and wrap it around an old fuse (with the foil side out) and reinsert into the fuse holder ... (this also works with aluminium foil for non-smokers)

With either option it will never blow ...

(I won't be held responsible for whatever else may happen) ...

[Mike.Gayner]

And once the fire goes out you can trace the burn pattern back to its point of origin, answering the mystery of where the grounding wire was.

[jonnyk5614]

Ok - just got back to the bike. Battery voltage is 12.5V. I can't check voltage with ignition on because the fuse blows instantly.

I know the old cigarette paper trick but I'm loathed to do it because doubt I'll find what it is before I break it


Sent from my iPhone using Tapatalk

[Gremlin]

You're in for a barrel of laughs... usually for fuses to blow like that there is a short somewhere.

You get to inspect the loom pretty much. Possibly where it's rubbed through to the frame or suchlike...

[neels]

You're in for a barrel of laughs...

Sadly this is true.

Probably an auto sparky would be a better bet, they're more likely to be tooled up for electrical stuff.

Either one of the magic boxes has a fault, or there is a wiring short. Best option is unplug everything one thing at a time, if the faults still there maybe time to keep blowing fuses until something gets hot enough to show on a thermal camera.

Either way, it probably involves killing lots of fuses finding it

[pete376403]

Buy a few fuses. disconnect every plug you can find. put in a new fuse. If it blows then the short is in the loom. if not, reconnect plugs until it blows again. the short is in what ever you plugged last.

[FJRider]

So was riding last night and the master blew. Pulled all the secondaries and the master blew again as soon as I put the key in "Park". So I unplugged the tail light, key to park, same again. Ran out of fuses and things to unplug and called the AA.

Am I best to call motorcycle doctors or an auto electrician?


Sent from my iPhone using Tapatalk

Do it all again in the dark. See what and WHERE it lights up ...

[eldog]

disconnect battery
see if you can find a electrical schematic for bike
do you have a multimeter?
if yes then use it to find the short to the negative side of the battery. when in park by connecting the + lead that was connected to the battery and use the ohm test. 0=short.
Most controls go through the secondary fuses after the main fuse. Unlikely they are blown and the main fuse blows as well.
have you done any work on the bike recently, disturbed wiring/tank etc
Disconnect things like the rectifier and generator, they usually have plugs etc.
Go about it in systematic way. See if the main supply splits at any point, so you can track down the problem or eliminate any main parts like ECU etc (if it has one)

check for Chaffing and animal damage, I have had the odd animal chew cables.

I worked on a machine recently, had a perplexing intermittant fault, worked for 5 minutes then stopped, each time a different fault. Turned out there were 2 wires which had been shorting between each other and the machine and also to loose connections in different combinations (machine moves and causes wires to bend/stretch apart etc.

In order to find my fault I had to assume nothing and work my way backwards and forwards till I found not one but 2 wires causing the problem. Like Sherlock Holmes - once you have eliminated the main suspects you are usually left with the impossible solution (something like that)

Something similar is found on some truck headlights, the + supply is connected to one side of the bulb only the - side is connected via a relay. If say the low beam filament brakes and falls down onto the high beam one it can blow the fuse but still operate off the high beam supply, usually with a dull glow making the lamp look OK. this was a trick one.

failing you finding the problem - there will always be an electrical person who can find the fault. good luck and patience

[FJRider]

And once the fire goes out you can trace the burn pattern back to its point of origin, answering the mystery of where the grounding wire was.

The smoke from the melting plastic on the burning wiring ... is a dead giveaway though ..

[jellywrestler]

Buy a few fuses. disconnect every plug you can find. put in a new fuse. If it blows then the short is in the loom. if not, reconnect plugs until it blows again. the short is in what ever you plugged last.

buy one fuse, hook it in series with a 12 volt bulb, and hook one end of the fuse and one end of the bulb into the fuse holder, even with a dead short the bulb will limit the current aqnd not blow the fuse, when you find the short the bulb will dim to maybe half, as half the voltage drop will be acroos the bulb and half across the remaining circuits.. really need proffesional help with this

[pete376403]

buy one fuse, hook it in series with a 12 volt bulb, and hook one end of the fuse and one end of the bulb into the fuse holder, even with a dead short the bulb will limit the current aqnd not blow the fuse, when you find the short the bulb will dim to maybe half, as half the voltage drop will be acroos the bulb and half across the remaining circuits.. really need proffesional help with this

I agree the current limiting bulb is a good plan. My way is the side-of-the-road version. My KLR had an intermittent short in the loom, this is how I found it.