New to XS650’s (and Yamaha) Build

Got the wiring all figured out on paper, can start chopping things up and putting new connectors on now
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Since I’m changing the gauges and won’t have a reed switch anymore, I understand the turn signal cancel unit will no longer work. Can it simply be unplugged with no issues? The previous owner had it plugged into the old harness so leaving it obviously doesn’t cause any problems. From the diagram it seems like it can also go with no problems but some searching has led me to a few different opinions.
 
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Your lucky day... I found this searching for something else...

Awesome, thank you! I started on the harness working from the headlight back, removing what is no longer needed and shortening leads as required. Will take a few days to get everything trimmed and routed then I can test it all before I re-wrap the loom.
 
Made some more progress on the wiring. I have everything in the headlight shell done and have worked my way to the backbone. Have a few leads to shorten still and the new fuse box to wire in. Then it can all be wrapped and routed and I can finish the back end
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Just need to wire in the new fuse block, put some connectors on for the rear lights, and bolt in the starter solenoid and the wiring is done. Looking pretty clean and tidy
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It’s a good thing that I pulled all the covers off the new harness and cut the fuse box out since while doing so I discovered whoever made the harness had the lead coming from the battery + going into the 10amp head light fuse rather than the 20amp main to the ignition switch.
 
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I'm just going to mention that sometimes these replacement harnesses have a glitch or two in them. The one my buddy got from Mike's for his '80G Special II turns the headlight on with the key. It shouldn't do that. The headlight shouldn't come on until the motor starts and the headlight safety relay gets tripped. We've confirmed all the harness plugs have the wire colors in the right places so the "glitch" has to be somewhere in the harness under the wrapping. Switched power is getting fed directly to his hi/lo switch.

Did you ever trace where this issue was coming from? I have a new Mikes harness and hand controls, I don’t have my starter hooked up yet since there is no oil in the bike, but I got everything else wired up and plugged in and my headlight is also getting switched power from the key. What I’m not getting is gauge lights or a brake light (running light is working but nothing from either brake switch). Signals, horn, high beam, neutral light, everything else is good. I have bypassed the RLU by connecting blue/black to blue/yellow, but the headlight power should still be running through the headlight relay, correct?

I ran out of time tonight so I’ll do a little more testing tomorrow,
 
No, we never did trace the issue down. My buddy isn't too concerned with it because the bike operates and runs fine otherwise. I don't think he was even aware of the issue until I pointed it out to him, lol.

Yes, the headlight power should come from the headlight fuse to the headlight safety relay, usually on a red/yellow wire. From the relay, once it's tripped, it is fed to the RLU on the blue/black wire. Usually that blue/black wire also sends power to your gauge lights so it makes sense you don't have them. They wouldn't come on until the relay is tripped (by the motor cranking or running). I'm not sure why the brake light isn't working.
 
No, we never did trace the issue down. My buddy isn't too concerned with it because the bike operates and runs fine otherwise. I don't think he was even aware of the issue until I pointed it out to him, lol.

Yes, the headlight power should come from the headlight fuse to the headlight safety relay, usually on a red/yellow wire. From the relay, once it's tripped, it is fed to the RLU on the blue/black wire. Usually that blue/black wire also sends power to your gauge lights so it makes sense you don't have them. They wouldn't come on until the relay is tripped (by the motor cranking or running). I'm not sure why the brake light isn't working.

Hmmm ok. I think I’ll wait until I have everything ready to fire up and once it’s running I can check these issues. Assuming the relay is working as it should, will spinning over the starter turn the headlight off so it’s not a power draw? If not I may spend a little more time trying to track down where the splice is or put in an on/off switch for the headlight.

I’m sure the brake light is nothing, probably a loose connection. I’ll check with a meter and make sure they are getting power tomorrow.
 
No, cranking the bike won't turn the headlight off. On a properly working system, sometimes it turns it on. That's what I don't like about that headlight safety relay, it only like half works. Sustained cranking of the motor is enough to get the alternator generating some juice, and that trips the relay, turning the headlight on, even though the bike may not be running yet. I'm all for the other relay in that unit, the one for the starter. I think you need and want that one. I just don't care for the headlight one and usually try to do away with it. On my '78 it was simple, just unplug the blue/black wire. The relay is still there and probably still doing it's thing, there's just no signal getting out because I unplugged it, lol. I just also completed the elimination on my '83. That took lots more doing, lol. I had to add an on-off switch of course, but then also send headlight power up into the headlight bucket to connect to that new switch, and change out the contact plate in the ignition switch so the tail light didn't come on with the key anymore.
 
No, we never did trace the issue down. My buddy isn't too concerned with it because the bike operates and runs fine otherwise. I don't think he was even aware of the issue until I pointed it out to him, lol.

I got the brake lights working (needed to remove some anodizing off the aluminum bats so the controls could ground). Couldn’t figure out why the gauge back lights weren’t working, so I pulled the harness apart more and discovered the blue power feed in the harness ran from the plug for the left control directly to the plug for the right controls...so either I somehow removed the power feed when I rewired or they missed it when they built the harness. So I split the wire in the middle and spliced it into the blue/ black which fed the headlight...with that solved I was feeling good, until I realized that the gauge lights shouldn’t be on (they were). I unplugged the headlight safety relay and nothing happened - lights stayed on. I pulled the headlight fuse, no change...so I started tracing wires and I discovered that the blue/black line coming out of the relay was spliced directly into the tail light power line running from the key switch, effectively bypassing the relay and the fuse. I’m wondering if this was on purpose incase the relay quits you’d still have lights? I might put a couple bullet connectors on at the splices so I can always unwrap the tape and jump them together if need be.

I’m sure it’ll be the same on your buddies harness, the splice is right where the rectifier plug is.
 
If you look at an '81 wiring diagram, maybe any '80 and newer diagram for that matter, you'll see nothing should branch off the blue tail light wire coming out of the key switch. It runs directly back to the tail light and license plate lights, that's all. Also, if you trace the instrument lights back, you'll find they should be fed from the blue/black wire that comes out of the safety relay, on it's way to the RLU. You shouldn't have just a rectifier plug, it should be a combined regulator/rectifier plug. But I'll check that one on my buddy's harness. His is doing the same, blue/black wire gets powered by the key. Unplugging the safety relay or removing the headlight fuse doesn't stop it.
 
Got the right side of the bike completely done - brakes adjusted / bled and the exhaust mounted.
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Got the plate light and bracket on. Not exactly how I envisioned it, I wanted to flush mount it under the fender but there wasn’t enough clearance.
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Just waiting for a new chain to arrive and then I can finish up the left side. The previous owner chopped the end off the kick stand but luckily he kept it so I have to weld that back on and then paint it.
 
Looks great!! Nice job.

Why would the PO have cut the kickstand?? Then again, why am I surprised? LOL

Keep an eye on your license plate/bracket...you may find the vibrations bend that mount loose or even break it...I've had to reinforce my mount a couple of times due to vibrations.
 
Looks great!! Nice job.

Why would the PO have cut the kickstand?? Then again, why am I surprised? LOL

Keep an eye on your license plate/bracket...you may find the vibrations bend that mount loose or even break it...I've had to reinforce my mount a couple of times due to vibrations.

Thanks Brassneck!

I have my doubts about the plate bracket, the hinge is very small and even tightened with Loctite I don't expect it to never move given how much these bikes can shake. The fender and lights are all rubber mounted which I'm hoping helps. Once I get it on the road (hopefully next week) to work the bugs out I will see if I need to put some reinforcement behind it. I don't want it falling into the rear tire treads and then getting torn off.

When I got the bike it had 10" long shocks on it and I'm guessing the kickstand was too long so they chopped the foot off about an inch up and added some round stock on an angle. Should be an easy job to weld the foot back on.
 
Had the wrong chain sent to me so while I am waiting for the replacement I cleaned up the old one and got it back on as well as finished up the kick stand. The bike is now completely back together (except for the new chain and I'm waiting on a short extension for the tach cable).

Last night I put some gas in her and after getting the carbs primed she fired right up! Headlight and gauge lights came on once it started as they should and all the electrical appears to be working perfectly. There is a bit of a gas leak from one of the carbs and it is idling too low - I went through the carbs in the fall when I was dismantling the bike and cleaned / set everything, so I'm thinking a float might be stuck. Worse case scenario I pull the carbs back off. Time to insure it and take it for a spin, I hope it stops raining soon :rolleyes:
 
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