1975 starting issues. with PO modified harness.

[Moisstink]

So, I just picked up this bike a few months ago and have been working on the gas tank and slight performance upgrades. Nothing that has to do with electrical in the least. I disconnected the headlight working on the forks and had to reconnect all the wiring. I run the bike once a week to get pumped on the process and make sure the carbs are mildly active (everything has seemed normal up to this point.

Anyway, a couple starts ago I noticed a little grey smoke from under the battery box. Today I went to start the bike and it started turning over and then nothing - dead.
Here is my situation, the PO said he hooked up a (alternator or coil) (I think) from a Harley that sits under the tank and did his own wiring set up. That's leaving in the dark with using the normal manuals on wiring.

Does the 75 only have one fuse?

My question is, what is usually attached under the battery box wiring wise? (rectifier). I am going to get at it this weekend. Any ideas on where to start. Currently I only have a harbor freight volt meter and no knowledge on electrical.

Just a good starting point would really help. Thanks for any and all info. I can shoot photo's of course of anything that may help with troubleshooting. The reason I have not done more research prior is that the electrical is not the stock wiring harness but I believe it is only slightly modified per PO conversation. Thanks again

 

[RFeng]

My 75 has just one fuse. There is no magic in electrical..just paths from this place to the next place. Follow the paths. Good luck!

 

[Brassneck]

This is going to be a bit tough from a distance...Sounds like there is a short somewhere. Yes, one fuse I believe.

I recommend you look through your wiring diagram, and identify what you do/don't have. Then start from one end and check the wires, connections and report on changes that may have been made. Likely we can then help with issues that exist.

 

[Moisstink]

Thanks for the reply, I appreciate it. I thought this thread was going to be a bust. I could not find out what is actually attatched at the bottom of the battery box and that is the area the smoke came from. Any idea what that actually is? It is a black rectangle around 2" by 3"with wires in and out. I am hoping it is just a short and when it cut out it seemed like that seemed like it may be.

 

[Brassneck]

That's your rectifier.

 

[nj1639]

From my experience the multi connectors in the headlight can't be interchanged....no duplicates. However, some of the bullet connections could be swapped if the color of the wire they're on can't easily be discerned.

One area that can short is where the wire bundles come through into the headlight bucket. IF the rubber o ring protector isn't fully seated you can cut a wire there or you can pinch and cut a wire placing the lamp back into the bucket, yeah, it can happen.

Seems anytime I work in the bucket pulling connectors I come away bloodied, sharp shyte.

 

[Moisstink]

I think the battery is holding a charge so I am going to start looking for burnt wiring and or spliced wiring. Electrical is not my thing but hopefully I will find the problem to help someone out down the line if not I may be picking your brains again. Thanks again!

 

[650Skull]

Start around the coil area if that is where he said some modification were done.

Check that fuse.

Do continuity testing, (doesn't require power), as well.

Test the wires from the rectifier to the stator

 

[Motorbreath22]

http://www.xs650.com/forum/showthread.php?t=61

Theres a thread with some different diagrams.

The PO FUBARed the harness on my bike and it wouldn't charge either. I just ripped it all out and did it right. On top of it all being wired wrong, some of the connections were just twisted together and taped up... no connectors no solder just tape...

I soldered, liquid electrical taped, and heat shrinked any permanent connection i made, Then I got some watertight connectors and fuse box from this guy.
http://www.easternbeaver.com/Main/Wiring_Kits/Fuseboxes/3_Circuit/3_circuit.html

$25 minimum but tons of selection for connectors

 

[Moisstink]

http://www.xs650.com/forum/showthread.php?t=61

Theres a thread with some different diagrams.

The PO FUBARed the harness on my bike and it wouldn't charge either. I just ripped it all out and did it right. On top of it all being wired wrong, some of the connections were just twisted together and taped up... no connectors no solder just tape...

I soldered, liquid electrical taped, and heat shrinked any permanent connection i made, Then I got some watertight connectors and fuse box from this guy.
http://www.easternbeaver.com/Main/Wiring_Kits/Fuseboxes/3_Circuit/3_circuit.html

$25 minimum but tons of selection for connectors

Thanks for the hook up on connectors. That does sound like the best way to approach this. The PO on this bike did go a little half assed on the electrical. I've never even heard of liquid electrical tape. Sounds interesting and worth some research.