Over charging - quick check in...

[triangleforge]

In trying to prep the 1998 ST2 for sale ( ), I'm chasing down one last electrical issue. Everything was running fine until I went to list it, did one last test ride before hanging the FOR SALE sign, and saw the voltmeter reading 17-18 volts. Yeesh!

Thinking (hoping) it might be the nearly done battery that wasn't holding a charge anyway, I ordered a new one and just installed that. Fired up and it's still running at 16+ at anything over 4K RPM.

My assumption is that it's time to order a new regulator, but is there anything else I should check first? I replaced a shorted stator in in a couple of years ago, but that showed up as a severe under-charge, so I don't imagine that's it...

Thanks!

[Speeddog]

That's a single-phase setup, yes?

Is it still completely an OEM style regulator, or do you have an aftermarket one fitted?

IIRC, for the OEM setup single phase they have a seperate ground wire for the regulator, or the case has to be grounded, or something like that.....

[triangleforge]

Single phase indeed, and it's currently running a Mike's Electric aftermarket regulator, re-located to under the bottom triple for more air flow.

I checked the ground wire at the battery, but your reply reminds me to take a close look at the full run of that wire - although I'm pretty sure I soldered the connection way back when, it could have gone bad somewhere along the line...

I'll take a look right now.

[ducpainter]

The single phase regs had a ground wire that attached via one of the mounting bolts.

[triangleforge]

OK, I checked the grounds and found that the ground wire screw at the back of the case was loose. Took it out, cleaned everything up & reinstalled, but it's still charging at 16+. That wire connects up to the negative terminal, which has a soldered connection (that looks good) into the wiring harness.

If anything, the bike has charged on the low side up until now - just a bit over 13.

[ducpainter]

OK, I checked the grounds and found that the ground wire screw at the back of the case was loose. Took it out, cleaned everything up & reinstalled, but it's still charging at 16+. That wire connects up to the negative terminal, which has a soldered connection (that looks good) into the wiring harness.

If anything, the bike has charged on the low side up until now - just a bit over 13.

Sounds like the R?R is done.

[Speeddog]

Just to confirm, we're talking about a ground wire specifically going to the R/R case itself, attaching under one of the bolts that holds the R/R to the bike.

[triangleforge]

There's not a wire running to the R/R mount; I'm not sure the location under the triple would offer a great ground anyway.

It's been long enough that I don't remember the stock configuration (which was in a completely different spot, mounted under the front fairing & prone to overheating), but as currently arranged, I've got two yellow wires coming off of the stator, two red wires merged and running into the red positive side of the wiring harness, one black wire that runs to the negative battery terminal (which is also connected to a ground cable that runs to the engine case), and a white wire that (for reasons I don't entirely recall) I ran to a fine, black sensor wire from the instrument cluster. Disconnecting that particular wire doesn't seem to affect the charging voltage in any way.

I imagine Nate's correct, that it's time to order up an new regulator, darn it.

[ducpainter]

When you do mount the new one add a ground wire from a mounting bolt to either the battery or to a location where a ground enters the harness.

[Speeddog]

AFAIK, the white wire runs to the charging indicator on the dash, so if it's not charging enough it turns on the light.

Definitely ask your R/R vendor about whether the case of the R/R needs to be grounded.
The OEM 3-phase units do not need to have the case grounded, AFAIK the OEM single-phase did, and sftermarket units... who knows.

[ducpainter]

AFAIK, the white wire runs to the charging indicator on the dash, so if it's not charging enough it turns on the light.

Definitely ask your R/R vendor about whether the case of the R/R needs to be grounded.
The OEM 3-phase units do not need to have the case grounded, AFAIK the OEM single-phase did, and sftermarket units... who knows.

Correct...and correct...

but a ground can't hurt.

[Speeddog]

Correct.

[Howie]

For test purposes grab a wire with two alligator clips, long enough to put one clip on the regulator housing, one on the negative terminal of the battery.  Charging rate stays the same, get a new regulator.  Charging rate returns to normal, run a good ground.

<snip>

but a ground can't hurt.

Yup!

[triangleforge]

Worth a try; thanks, Howie!