Electrical Problem (Fuse Blows During Start) Pictures Included

[vincemoccio]

I purchased this bike used from a friend. The bike seemed to have some electrical issues because every time I would ride, one out of the 3 fuses would blow, losing power to the tail light and headlight. The main fuse never blew. Just one of the 3 others. I though it was caused by the rinky dink, 2 wire taillight. So I replaced that with a tail from lowbrowcustoms. Everything is connected correctly. Now, everytime I start the bike the same fuse blows. The ground from this fuse goes to the wiring harness, that is attached to watever box that is on the side of the battery (regulator rectifier). The other wire is a red and white wire that leads up to the little clylinder where the spark plug comes from (I believe it is the ignition coil). Sorry I am new to fixing motorcycles. You can see in the picture that I am holding the fuse that keeps blowing. Most of the wiring is pretty much a huge mess, and I am not sure where to start. Most of the wires are sodered together pretty good. But a lot of wires go from 2 to 1. HAS ANYONE HAD THIS PROBLEM AS WELL. IF SO WHAT WILL FIX IT. Thanks guys!

 

[XSLeo]

Well to start with fuses don't go to ground, they are between the power source and the load. That way if the circuit overloads the fuse blows to protect the circuit.
You have four fuses, One is the main fuse and should be a 20 amp. It has red wires going to it. One is the headlight fuse, this should be a 10 amp, it has red/yellow wires. One is the signal fuse this has brown wires. One is the ignition fuse and has red/white wires.
The headlight fuse powers the headlight. It sends power to the safety relay where when the engine starts the alternator sends power on the yellow wire to trip the relay, turning off the starter and turning on the headlight. It does this by sending power out on the blue/black wire to the reserve lighting unit and the instrument lights and the tail light.
The RLU sends power out on the yellow/blue wire to the headlight dimmer switch, from there it goes to the headlight hi or low beam.
On the fuse that blows what colors are the wires the fuse holder hooks to?
Can't tell in the pics.
Leo

 

[XSLeo]

Was just reviewing your post. You say you have three fuses. That's not right for any year.
What year is your bike?
With a bunch of soldering your PO has been modifying the harness. You might have to tear it all out and start from scratch. Not as hard as it sounds.
Leo

 

[vincemoccio]

Thanks again LEO, the two wires coming into the fuse that keeps blowing are 1. a red wire with a white stripe coming from the ignition coil (near the front of the bike under the gas tank) and 2. a black wire feeding into the wiring harness for the regulator rectifier. Something is causing the fuse to blow. What would be the best way to go about testing the wires to see which wire is causing the fuse to blow? What do I use to test, how do I test it. I was going to redo all of the wiring but do not think it would pin point what is causing the fuse to blow.

 

[vincemoccio]

No turn signals. 1978 xs650, does have 4 separate fuses. Probably due to the aftermarket headlight, speedo, and tail light. Whats the easiest way to pin point a bad wire? Continuity test?

 

[XSLeo]

The red/white to the coil is correct. The black wire to the black of the reg/rec is ground.
On the stock wiring power comes from the battery through a main fuse to the key switch. On the 70 to 78 bikes they had just one fuse. The 78 up bikes had four fuses.
That's why I asked about the year of your bike.
On the one fuse bikes after the switch power flows out on a brown wire which feeds the engine stop switch. some years the engine stop switch had a brown wire feeding it, some a red/white wire Either way it gets power. From the engine stop switch power flows out on the red/white wire to the coils. If a points bike, On the TCI bikes it has just one coil and both the coil and TCI box get power on a red/white wire.
We can't go much farther without knowing the bikes year.
Leo

 

[XSLeo]

With all the aftermarket parts your wiring may be in quite a mess. I might suggest finding a wiring diagram that matches what you should have.
Up at the top of the page is an XS650 TECH button, this leads you to a list of topic, under each topic is a list of subjects. Under the electrical there is a thread Some Wiring Diagrams.
Scroll down to fine the 78 diagrams with 4 fuses. The switch from one fuse to four happened in 78. The standards had 1 fuse the Specials the 4 fuses.
Once you find the diagram you need to start tracing the wires. Start at the key switch and follow the diagram checking for voltages.
Your switch has three wires, red is power in, Brown is power out to most of the bike. blue/yellow is lighting.
In your diagram if you trace the brown wire you will see that it sends power to three of the fuses, It comes out of the one fuse on a brown wire to the light checker, brake switches, horn, flasher canceling unit, regulator, and the neutral light and tail brake failure light. Some of these things might be deleted by your PO. But all should get battery voltage.
If you find a pint that doesn't have power you need to follow the wire back to find where it gets lost. once you find the power just fix the break.
You use this same process with all the wires. It will take time and patience. Finding all the places a PO changed things and making them right can be tough. It might be easier to remove the harness and strip it apart and use it the create a simpler harness. You can reuse the wires and connectors if in good shape. If not you can find new connectors at Mike's or other places on line. Wire can be found locally or online.
Leo

 

[weekendrider]

The wiring done on the right side(instead on of top of the battery) leads me to believe it was a single fuse system/loom used on the standards through 79.
vincemoccio yours looks to be "custom" for sure.

 

[XSLeo]

Weekender, yes he has one big learning experience coming up.
With aftermarket parts, lots of soldered joints, the Po definitely did some modifying.
With time and patience he will get all the bugs worked out. Once this happens the feeling of confidence in himself and the bike will be greatly increased.
Lot of work, maybe. Worth the effort, definitely.
Leo

 

[vincemoccio]

Thanks gentlemen, ill dig into it and keep ya posted!