Ground wire from R/R burning

[Doubleyoupee]

Hi all,

After reinstalling my XT600 3AJ engine and turning it over, the black ground wire from the R/R started smoking.
It's this wire that is connected directly on the R/R: https://i.imgur.com/7TtArlW.jpg

I have some questions

1) Why is this wire not on the diagram? https://i.imgur.com/LvRfrZF.jpg

2) What's the exact purpose of this wire? How can a ground wire become hot? Is the R/R dumping unused current through this?

3) Can I run a wire directly from the ground bolt on the R/R to negative terminal on the battery?

Finally, might be related or not:

4) Can I turn over the bike with coils disconnected? Is this why the R/R got overloaded?

Thanks

[scottieh]

I modded my wiring and ran a thick ground wire from the neg battery terminal directly to the R/R ground. If i remember correctly it is a common modification and has been suggested many times on this forum.

That said it should never be a hot wire. I’ve never heard of that wire smoking.

[Doubleyoupee]

OK I'm a god damn idiot..........

At work something dawned on me.
I remember getting distracted when connecting the main battery ground cable because I noticed the smaller ground cable from the ground cable and decided to connect that first. But I never remembered removing the startermotor bolts to connect the ground cable.

So yeah, I forgot to connect the ground cable and the starter motor searched for another way to ground. I really hope nothing got fried. Never expected the starter to turn so fast without that main ground.

Already replaced the molten connector and now all good. At least I've got oil pressure.. so that's that

[Doubleyoupee]

Well, first start yesterday - and it fired right up. At least the CDI is still functional

[scottieh]

Nice work. I almost burned my bike to the ground when the starter main wire arc’d past the fiber washer against the starter body and spun endlessly until i disconnected the battery.

Well, first start yesterday - and it fired right up. At least the CDI is still functional

[Doubleyoupee]

Nice work. I almost burned my bike to the ground when the starter main wire arc’d past the fiber washer against the starter body and spun endlessly until i disconnected the battery.

Well, first start yesterday - and it fired right up. At least the CDI is still functional

Hehe, I have a fire extinguisher ready

Anyway also measured my R/R after I got it running pretty stable.
It appears to be functioning, however charging voltage is a bit weak, around 13.4V regardless of RPM. Will try later with lights connected.
However, manual says the no-load regulated voltage should be 14.3-15.3V. Isn't 15.3V too high? I normally read about 13.5-14.5V.

[dzl]

Hey Doubleyoupee.....yes if lights not on you would expect to see 14.5V.....quite often if the charge V is slightly low the voltage reg may not actually be sensing the actual battery voltage. Possibly due to slight resistance on the red wire from the VR to the battery. This can be due to old dirty connectors and lugs in the circuit. Make sure all connections clean tight at the connector and the inline fuse in your particular circuit. Check Resistance with a meter from VR red wire to the red wire at the batt. 1 ohm or less is ideal. As a test, if you were to run a wire direct from the VR red terminal direct to the batt + and bypassing connectors and fuse etc, you likely will get higher charge V