New to the xs world

[JacobT]

Hello everyone. Just picked up a 1980 xs400 special with just over 10k miles on her with a clean title for the sweet price of $180.
Got it home and they had the wire from the starter solenoid that goes to the battery connected to ground. I'm thinking well I can hook it up right, throw some starter fluid in the carbs and hear her fire up. Unfortunately that was not the case. I'm not getting spark. It will spark once and once only on the left side. I believe the right side coil is probably bad. Any ideas on why it would do this? My next guess would be to try a different ecm/cdi whatever you want to call it. The harness is not hacked up, except for a shoddy re soldering job on the fuse panel which I will be replacing. My goal is to turn her into a café racer, but I want to hear her run before I strip her down to nothing.
Also on the last picture, this was bolted to the battery box. Doesn't look like an oem part to me. And theres no place to hook it up on the harness.

 

[spectra]

Nice score and that doesn't look like an oem part to me either.

Test the coils first and see if they are in spec. then trace the wiring and make sure things are hooked up correctly as you stated you found wires already in the wrong spot.

 

[BBS360]

Non-stock rectifier in the last pic.

 

[JacobT]

Yeah I was thinking that’s what that was. P/o had no idea what he was doing I think.
No If im right these have a separate regulator and rectifier or no? I had a reg/rectifier that plugged right in to the harness. 3 white wires a red and a black. And if not is the small unit bolted to the battery box w 3 wires running from it an ic igniter? I’ve been going through the manual but not 100% sure on this.

 

[BBS360]

Battery box holds the separate regulator, rectifier, and ignition unit. The regulator is silver and has a green, brown, and black wire.
On the bottom should be the TCI unit with a seven pin connector.

Your description matches the stock standalone rectifier.

 

[JacobT]

In the meantime I went through the carbs which really weren’t as bad as I thought. I cleaned the living crap out of them though. Even used some bar keepers friend to polish up the floats.

 

[JacobT]

So I just put a new set of coils on the bike. Same issue. One spark only on the left side only. I realized if I toggle the kill switch on and off the left one will spark each time I turn it on. Anyone have any ideas as to the culprit. My next guess would be the tci but I don’t want to keep dumping money in stuff that’s not needed for her. Also on a freshly charged battery I’m getting right around 9.6 volts at the coil. Is that enough for them to spark or should I run a relay to send voltage directly from the battery to the coils. Thanks.

 

[BBS360]

Voltage seems low. I was getting 10.5v at the coils when I checked a while ago.
I did the relay mod but just cleaning up the connectors should help.

Try cleaning up the TCI and pickup coil connectors.
There's a resistance test that can be done on the pickup coils. Worth checking. Info in the Haynes manual download on the forum

 

[JacobT]

Thank you. I will be doing this tomorrow!
At least all and all With buying the bike, new float bowl gaskets and coils I’m at roughly $220. Not too shabby.
I’ve done the coil mod on my kz650 so yeah I’ll do it on this too for piece of mind.

 

[JacobT]

Well I checked out the pulse/pickup coils. I’m getting about 1.7 mega ohm. I guess that’s how you say it. So I’m thinking it needs a new one. I think I’m just going to source an older ignition advancer and get a pamco electronic ignition. This way I’m not hunting down these gremlins and wasting my time with used 37 year old electronics.

 

[JacobT]

Cleaning up the motor. Guess I need a cylinder. It’s weird how these two pin holes are pretty much in lign with them selves. Wonder if it was a casting flaw or something. Or detonation.

 

[NewHavenMike]

I bought a used jug on Ebay a while back and it had the same markings on it, I sent it back and got a refund. The one I have now has a low spot on the bottom part of the cylinder but it seems ok. So you had electrical problems, but decided to tear down the engine anyways?

I will say that your $200 bike just turned into a $2500 project lol. Once you get into the engine, thats it..

You might be able to get past those pits by going the max over bore size. You need to get the max bore specs and bring it to a machine shop and see if the new bore size will clear the pit.

 

[JacobT]

I’m not too worried I’ve found some nice cylinders with pistons for fairly cheap. $2500. That’s funny. I’m making the wiring harness myself. Did that w my kz650. Going to get a pamco ignition. I figure new tires and everything else I need I’ll keep it under $700. I work at a powersports company so I get some pretty sweet deals on parts.