What to do, what to do? (CDI dilemma)

[RobXS650]

Fellow XS’ers!

First off, thank you again for the warm welcome the other day. Nice to know there’s a place for people like us. ‘Voor elke gek, een plek!’ Like the saying in Dutch goes.

I’ve been puzzling over something for days and can’t figure out the best approach. So, once again, I return to drink from your well of infinite knowledge (and patience)!

The fact that I’m redoing the wiring (Wiring XS650 1979) isn’t exactly for fun. The problem started like this: after connecting the VM34 carbs and especially after syncing them, I drained the battery and had to recharge it. As you might have noticed the other day, the battery is tucked away in a well-hidden battery box with two switches: on/off and one for the lights. After charging, I briefly tested if the lights worked (with cover and the switches slightly off the bike) and accidentally touched something on the frame (I think), causing a short circuit.

Red wire and red/white wire seem burnt

I see two slightly burnt wires under the on/off switch. According to the wiring diagram I made, it’s the red wire (which goes with a fuse to the battery and the stator) and the red/white wire (which goes to the Newtronic electronic ignition), both coming out of the on/off switch.

Red/white to Newtronic (inside looks old and painted with some protective stuff, but seems fine?)

Now the choice is... to either rewire the old system, connect everything, and hope for the best...

Or, since I’m already working on the electrics and have everything open (and I need an new excuse to spend time in the shed this winter ), buy a new ignition system.

In that case, I’d likely go for the Boyer, combined with a new reg/rec. Apparently it is better for all systems involved to upgrade to reg/rec in one, when using the Boyer set.

• Boyer cdi 236€: https://www.heidentuning.com/xs650-...dware/ignition-cdi-boyer-bransden-detail.html
• Reg/rec 104€: https://www.carmo.nl/index.php?main...C0ToQAvD_BwE&zenid=o57lkurvejg3cbq1o156ejvud7

The tricky part is that I don’t know how far the short circuit went or if the ignition box (or other components) is damaged. Realistically, could it just be those two little burn marks on those two wires and everything else could be fine?

I also can’t find any info online on the Newtronic black box, to replace it or how to test it (for example, how to measure the inner workings?!) without the engine running or powering up the electronic ignition.

I’m still learning about this (electronic) stuff, and I don’t want to damage other components by just hooking it all up and testing it.

Normally I’m pretty self-sufficient, so I won’t be posting questions like these on a regular basis. But like I said, I don’t want to do something stupid (again) and end up with an even bigger problem.

By the way, I’d rather not spend €236 + €104 on a Boyer and new reg/rec unless it’s really worth it, especially in the long run.

What to do, what to do?

 

[Its been a long time]

I can't answer the "what to do" question but that ignition box looks to me like it's had the potting compound removed. I had a couple of those systems and the back was full of potting compound. For me, that's a big red flag.

Secondly, I disagree that a combined rectifier/regulator is the best option for the standard XS650 charging system. I recommend you read the technical section here about the charging system and think about using a standard three phase bridge rectifier and an automotive regulator. I did my bike that way for less than £25 including making new sub-harnesses for them both.

Lastly, yes I think the Boyer ignition system needs a good solid voltage. A good battery and refurbished charging system will be fine.

 

[RobXS650]

I can't answer the "what to do" question but that ignition box looks to me like it's had the potting compound removed. I had a couple of those systems and the back was full of potting compound. For me, that's a big red flag.

Secondly, I disagree that a combined rectifier/regulator is the best option for the standard XS650 charging system. I recommend you read the technical section here about the charging system and think about using a standard three phase bridge rectifier and an automotive regulator. I did my bike that way for less than £25 including making new sub-harnesses for them both.

Lastly, yes I think the Boyer ignition system needs a good solid voltage. A good battery and refurbished charging system will be fine.

As new components go, I think I will give that phase bridge and automotive regulator combo a good look. I remember reading about that as well. Good one.

It doesn’t feel right to fix an electrical problem while have something in the system that seems really old and worn. But what do I know.

So Boyer, new wiring, new battery, but saving money on the regulator/rectifier…

 

[Its been a long time]

As new components go, I think I will give that phase bridge and automotive regulator combo a good look. I remember reading about that as well. Good one.

It doesn’t feel right to fix an electrical problem while have something in the system that seems really old and worn. But what do I know.

So Boyer, new wiring, new battery, but saving money on the regulator/rectifier…

Good plan. Give the alternator rotor and stator a good inspection especially electrically as per the specs given in the technical library here. Fit new brushes to the rotor/stator and with the other stuff, you're good to go.

 

[jaybar6]

the red wire goes to the battery via the fuse, why did not the fuse blow?
the red/white wire goes to the coils and energizes them.
when you throw the on/off switch, the red wire is connected to the red/white wire.

 

[RobXS650]

the red wire goes to the battery via the fuse, why did not the fuse blow?
the red/white wire goes to the coils and energizes them.
when you throw the on/off switch, the red wire is connected to the red/white wire.View attachment 335332

That’s what I thought. I checked the fuse with a multimeter and it seems fine. Doesn’t look damaged either.

UPDATE: just checked again, but it doesn’t read 0, but 0.5 - 0.7. That’s not 1.0, but probably not a good thing…

 

[jaybar6]

sorry rob, yours is a 1979 electrical circuit, here: orange and grey

 

[RobXS650]

sorry rob, yours is a 1979 electrical circuit, here: orange and grey
View attachment 335334

The fuse is located between the battery and the switch. Unfortunately not between te switch and the ignition box.

Orange and grey to/from the coils don’t seems to be affected.

Oh well, stripping and rebuilding the wiring anyway. Already found some turn signal wiring that was still in the tree…

 

[jaybar6]

the red/white wire is the power line (12v) from the switch. it goes to the coils and powers up the Newtronic black-box . there should be a fuse (10amp) on the red/white wire to protect the Newtronic box.

the red wire out of the Newtronic box goes to the timing circuit and from this sends an electronic pulse down the red wire to cause the plugs to spark. probably by dropping the voltage to zero on the orange and grey wires alternatively. thus creating a spark at the plugs as the magnetic field collapses.