GT550 fuse blows immediately

[Knut]

Hi,

The 20A main fuse on my GT550 blows immediately when turning on the ignition, like in a second. I'm really not good at electrics, so hopefully someone can point me in the right direction what to look for. I read some similar threads about the same but it differs somewhat as mine blows immediately while with the others it took some time. I checked briefly the battery wiring for any shorts and worn isolation the other day but couldn't find anything obvious.
I appreciate all help and advice.

[pull the wire]

Trying to find electrical shorts can be aggravating. You did not mention if your bike had been functioning properly and this just now happened. Check your battery first and all of the battery cables to be sure they are clean and tight. You will find it much easier and less expensive to substitute a 20 amp circuit breaker in place of the fuse. The circuit breaker will simply get hot and break the current flow and when it cools off will reconnect the circuit. It's easier and cheaper than having an endless supply of fuses. You can just start disconnecting circuits until the problem stops. Headlamp, tail lamp, handlebar switch wiring and so on. It could be somewhere in the harness near the steering stem where it has to bend so often when turning, or inside the headlamp where many of the harness connections are.

Good luck

Doug

[pearljam724]

A wire is attached incorrectly or an unprotected wire is being grounded somewhere. Look closely inside the headlight bucket being sure nothing is making contact with the bucket and all of the wires are protected from making contact with one another. It helps to zip tie all wiring and use the fasteners attached to the bucket to prevent wires from moving around and making contact. I would also inspect the ignition switch. Remove it, take it apart. Wiring in ignition switches can be pulled from it's solder inside the switch due to side to side motion of the handle bars. Check the wiring on the back of the rectifier too. Check all wiring for heavy dirt, grime or oxidation. Wire ends must be protected and clean from it or it causes over heating of wire and components.

[Knut]

Thanks for advice, I'll start troubleshooting this afternoon. Will try to get hold of a circuit breaker. I will also disconnect the Newtronic box to prevent any damage to it.

This happended suddenly as I should start her up the other day, it was all fine when I parked her the night before. I went through two spare fuses to check, and all three times it blew the second after I turned the ignition switch. My friend, who I bought the bike from, knows his stuff and would never build it with a ratty wiring, so it leads me to think of a worn component, worn isolation where it rubs onto something, or an open end somewhere if a lead has come loose. Normally I would ask him but now it's time to learn this myself as he is very busy with work and other things at the moment so I don't want to bother him with this right now.

[jabcb]

Disconnect the battery & check the resistance with a multimeter.
You might be able to find the short using a multimeter & the process of elimination.
Also look in the wiring diagram for your bike.

[Desert_75]

My 750 was doing the same thing, turns out the wires had worn through underneath the engine, prior to entering the rubber plug that leads to the points. Pull those apart and shrink wrap accordingly.

[Knut]

Just thought to update this, I found the fault. All wiring and connectors were fine. Water and grime had caused a short in the right hand handlebar switch (killswitch). Solved with brake cleaner, a small pipe brush and a little WD40

[kettle kid]

Just thought to update this, I found the fault. All wiring and connectors were fine. Water and grime had caused a short in the right hand handlebar switch (killswitch). Solved with brake cleaner, a small pipe brush and a little WD40

I was going to say ..( you beat me to it) inside the headlight, disconnect the switch wires ( left and right ) and then turn on the ignition.. All ok.. Plug in the left switch... All ok.. Now plug in the right kill switch ( 3 wire plug ) fuse blows.. There's your problem.. But you found it.. In the future On any electrical fuse blowing problem, I would start with disconnecting everything you can, turn on the ignition, and then start pluging things in, until you find the fault...

I have been restoring Suzuki,kawasaki, & also laverd switch gear, and the things I find inside... Match sticks..super glue..bell wire..dead spiders, cobwebs.. And mud and dirt, witch blocks up the drainage holes in the bottom, then you get a build up, of moisture, shorting out the switch.. Well done that man... Sometimes they get in a right state... This was one of the worst..

[Knut]

You're right, switches are perhaps the electrical component that is most exposed to water and moist, they are lubricated with light oil to prevent corrosion, then dust and grime from the road collects inside and sticks to the oily surface, trapping more water and moist, and in the end cause some sort of malfunction. And they are probably rarely maintained (speaking for myself ). Probably the best thing to do is to open them once a year and clean them out with compressed air and use a slight shower of thin oil for electrical components just to prevent moist corrosion.

Nice job on that switch btw

[kettle kid]

Thanks Knut, one of the worst one's I have had to refurbish.. Unlike the Suzuki switch gear, kawasaki switches are stamped with a three did get number.. Making them original too the Kawasaki's ...