Anyone here with experience replacing the wiring system?

I purchased a 1983 xj550 a little while ago and since then I've been in the process of fixing it up. It has plenty of issues, many of which were being caused by faults in the electrical system. This appears to be because the guy I purchased it from tried to make a few modifications of his own. He... didn't do the best job...
Long story short, I'm currently working on replacing nearly every wire on the bike, and I was wondering if any of you guys could give me some advice on things like what you did, how you did it, what you replaced what with, where to find replacement parts, things that are commonly replaced because the oem part always breaks, wire gauge sizes, etc.
Really any advice would be appreciated.

Also, where can I find which wires are supposed to be doing what on things like the regulator rectifier? Like how much resistance some wires should have, and stuff like that.
Would it be in a service manual?

This process has been a pain in the ass, but I'm really enjoying it.
I see why there's an entire forum dedicated to XJs.

Thanks everyone!

 

There's a diagram here that should help:
http://www.lumien.se/the-yamaha-xj-550-fully-interactive-electrical-diagram/

Plus, the catalog page here has a ton of info:
https://www.xjbikes.com/forums/threads/xj-parts-catalog-section-d-electrical-system.44641/

 

The best way (for reference I used to work on macines that have complex wiring harnesses) is to buy a good, used wiring harness from someone, and swap it out.

 

I actually found that interactive diagram a couple of weeks ago and forgot all about it. Thanks!

 

How reliable are the old harnesses off of a website like ebay?
I guess even if it's 35 years old it's still good right?
I'm worried that with something that old, i'd have issues with the wire insulation cracking and stuff.

 

are there any newer motorcycles that use the same (or a similar) wiring harness that I could use instead of one of the older ones?

 

I can say that I lucked out with my bike. I think it was stored indoors most of it's life and the plastics and wiring was in pretty good shape. I've replaced (upgraded) the fuse box, but that's really it.

 

Typically, harnesses don't go "bad", but they do get destroyed.

Old harnesses suffer mainly from 2 problems: missing connectors (they were cut off to make harness removal easier) and corrosion on the terminals.

Connectors can be replaced, most are available (along with new terminals and the proper crimping tool), we have them in stock.

Terminals that are present but corroded need to be cleaned, which can be a time-consuming and sometimes frustrating task, but is well worth the effort (even on bikes still wearing their original harness). Then protect the terminals by stuffing the connector shells full of di-electric grease (or similar) to slow down/prevent re-oxidation.

Insulator cracking is rare and easily repaired with vinyl insulation tape (use good quality tape, not the Home Depot variety).

 

Well that's good news. I'm really not worried about the connectors. Those are easy to replace. It's the wires I'm concerned about.
Is there a brand or two of tape you could recommend?

 

Scotch-Professional-Grade-Vinyl-Electrical-Tape-Super-88

I will typically cover that with friction tape in areas where the harness moves (near the headstock for example).

3M-Temflex-Cotton-Friction-Tape-1755

 

Awesome, thanks!

 

So... I just had a little brain blast.

I have a wiring harness from the bike, it's just old. The reason I'm trying to replace it is because some guy modified it. But I have the diagram. So if i just go through the diagram, Identify and label each wire, undo what the guy changed, and replace or patch any of the damaged wires, I should be good to go. Right?

 

Right. Just consider what your time is worth, factoring in that you will be learning along the way.

If you need to make any splices, use shrink-wrap crimps or a linesman's splice
how-to-splice-wire-to-nasa-standards
Just take care to keep the splices away from parts of the harness that need to bend, cutting the wire and splicing further away if necessary.

 

That is a nuclear-grade splice right there! Would be even stronger on braided wire.

Pretty much, the only area where you might run into an issue is if there are connectors missing (or replaced with incorrect connectors), then you'll also have to "match up" the wire color combinations to the other harness (or "device", in case of cube relays or the TCI) to determine what goes where. The factory wiring schematic (drawing) is usually correct in their wire colors, but, the locations of the various objects along the harness is not always correct (nor is it really intended to be, for that purpose). Also, use the wiring diagram on page 7-28 of the factory manual, it shows the connectors (both the type of connector shell and the wire orientations within the shells), rather than using the circuit block diagrams in Section 6 of the service manual (which are good for troubleshooting, but not so good for what you are trying to accomplish).

 

That's a great point that I haven't considered yet. I'll be sure to keep splicing away from bends. Thanks!
NASA standards sounds pretty legit lol

 

Update on “progress”...

I purchased a new-to-me oem harness off of eBay.

Now when I turn the key, the neutral light comes on (and dimms when I set the switch from “off” to “run”), I can get the red warning light to come on, and the side stand relay clicks, but nothing else works.

I checked the reg/rec, starter solenoid, battery, starter motor, those are all good.
Both handlebar assemblies are new, so new starter button.

I’m stumped...

 

Perhaps you have a sticky sidestand switch that needs to be cleaned and lubricated?

 

Brian S,
I thought you were going to use the original harness and just do the trouble shooting and fix it? Sense you have changed out the harness, did you make sure that all the connectors were cleaned and used dialectic grease when needed?

With wire troubles I find it best to take your time. Get a pad of paper and write down the issues you are having. If it is only looks but all the electrical still function, take it slow and do one wire at a time. Just clean up the harness one wire at a time so nothing gets confused or crossed.

As K-moe mentioned above, it will take time and is a good leaning exsperiance as well.

Good tests equipment "multi meter, test light and even a good 12v donor battery. Using the donor battery and spare wire to test all the lights at the connectors takes time, but it will save you from having to turn the swx on and off all the time.

Before you start to poke around testing all the wires, if your bike has electronic ignition, unplug it from the harness so nothing happens to it.

 

do you hear the starter safety relay close(click)?

remove the side stand relay to bypass it and eliminate it as problem.

open headlight bucket disconnect the clutch safety switch green connector and put a jumper wire across the 2 wires in the connector.

above things bypass sidestand switch and clutch safety switch.

make sure bike is in neutral and see if it turns over.

how do you get the red warning light t come on ?


stock handle bars?

turning on the run switch draws power could be why the blue neutral bulb dims.

when pressing starter button is that when the red oil light comes on?


did you install the diode block in the head light bucket?

there is a harness connector near the right ignition coil it goes to the right controller make sure it is tight and connections are being made.