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@Goofman speaks about this stickering business as if there is plausible deniability . . . Happily, the matter met the approval of the cheerful Sp'Honda-Raider . . .

@Sam P, let's try to take the oil pressure light out of the equation. You reported the oil light illuminates when the connector to the switch is grounded. Connect your Ohm meter and measure resistance from the switch post to ground, key off. The switch should be closed/grounded with no oil pressure, resistance: near 0 [oil light on will come on KOEO]. If the switch is open with no oil pressure (engine off)/ resistance = > 1 < [no oil light KOEO], then the oil pressure switch has failed and has nothing to do with the odd behavior of the "battery/charging" light . . .

"Weird bollocks ", indeed! I have put mySport on the lift, removed the seat, pulled the regulator connector apart, probing with the DVOM, trying to fathom why @Sam P's Sport won't charge and how the strange warning light behavior might inform a solution . . .

The derived protocol takes more attention and involvement, but improves the outcome. Is it worth it? I can say, with certainty, mySport's performance (and reliability) is significantly better with optimal charging and battery strength. YMMV

If I am reading this correctly, the odd charging light behavior started after the battery got cooked. And did not change with the new stator and regulator? Makes me think something also got cooked in the harness/connectors - seemingly in the circuit involving the instrument panel . . .

Exactly. Over time, that low float voltage (below Odyssey's 13.2 minimum threshold) will "shorten battery life". How much? Unknown. But undesirable. Your new charger is likely configured to address this. Rather than the "tender" approach, I have grown fond of charging the Odyssey with at least 6 amps up to 15.0 volts, then float charge at 13.56v (what my EnerSys charger will float) for maybe 24 hours, then terminate charge and let the battery gradually discharge. Repeat when the static charge reaches 12.65v. _____________________________________________________________________________________ > LESS voltage on trickle/float is NOT okay. Odyssey states that floating under 13.2 damages the battery: "Note, however, that the charge voltage should not be dropped below 13.2V as that will cause the battery grids to corrode faster, thereby shortening the battery life."

Pretty sure @Sam P posted the answer to this on page 8 . . .

With the trickle charger connected to the battery, test the voltage across the battery terminals (charge voltage). Most common "trickle chargers" will be below Odyssey's 13.2v minimum threshold.

I get 15.9Ω with this same test.

Did you start it to see if it charges with the jumper wire to the black wire of the regulator? Next, I would jumper the other side of the connector (battery voltage to the white wire and the connector rotated to connect the black --> red/black. I don't think the light will come on at all in that configuration. Looking for the charging voltage to come up while running above idle. . .

Good call on getting the approved charger. Odyssey states that float voltage below 13.2v will shorten battery life. What is your trickle charger's voltage?

How about running a jumper wire from the battery positive to the black wire into the regulator (turn the connector 90 degrees to leave the white->blue connected). KOEO: battery light on? Start up and normal charging at some rpm with no 4000 rpm light?

I so love Susan Tedeschi. Don't tell Derek Trucks. Or my wife. Great web find: Susan in 2001. No wonder Derek said, "Gotta marry that girl" . . .

Nicely simplified schematic. Just a note, that the red/black output from "Headlight" Relay (#2) does supply the brake light (also horns), but not the entire left switch cluster (i.e.: not the turn signals). Perhaps Fuse #5 (F5) should be indicated ahead of the Starter Relay. Turn signals are Fuse #7 (F7)

Let's talk batteries, @Sam P. Did you replace the "destroyed Odyssey" with another Odyssey, or something else? A voltage loss from 13.0 to 12.7 in an hour is not a good sign for an Odyssey. There are specific parameters to "condition" the Odyssey that may help contribute to a solution. "trickle chargers"/ "tender" are known to be damaging to the Odyssey battery unless the voltage is adequate, yet will not "charge" the Odyssey with sufficient amperage (at least 6 amps).

Here is the @Kiwi_Roy rendition ( hosted on @Weegie's dropbox ): https://www.dropbox.com/scl/fo/no8adkie1sl6frnc2qmm8/ALzrUXsngCqMRtfMR1cXedE?dl=0&e=1&preview=Guzzi+Wiring+-+Simple.pdf&rlkey=8x5byzd4ux3107610i22ig5v6&st=3xbx7rbu

From Carl Allison [ @callison ] on thisoldtractor . . . What is not correct on this diagram is the the reference/warning circuit wires from the regulator are white and black then change, at the flat "SAE" connector, to blue and red/black. https://www.thisoldtractor.com/guzzi007/pdfs/1999_V11_sport.pdf

" recommendation for next steps " . . . For starters, I am going back over all of the outcomes. Like @audiomick, I suspect a high resistance problem (bad/corroded connector) in the mix. I suspect this is in the "voltage reference"/warning light wiring. The oil light issue may be a clue. @Sam P, can you pull the connector from the oil switch and ground it (KOEO) to see if the oil light illuminates?

I think: cigars all around. I cannot imagine another online community with this much enthusiasm dedicated to helping another member solve a problem.

Just an addendum: the turn signals are on their own circuit.

On the main ground: looking for tha same approach you used on the timing chest ground: clean, remove any paint, DeOxit ( maybe a "star" lock washer to dog the connection in).

I told, y'all, already: "Boys, I'm goin' in " . . .

And that is with all of the relays installed? That harness red/black is the voltage reference to the regulator's black (input) wire. Should be battery voltage coming out of Relay#2 . . . edit: Both the blue and especially the red/black wires look rather kinked going into the back of that connector. If they are straightened, or "wiggled", does the voltage change?

Voltage on the red/black wire, KO/EO?

Cleaning and securing that main ground along with restoring the regulator's harness ground can't hurt. Next, we are going to have investigate the connectors under the tank.