What's this GS550 electrical part?

[Anonymous]

It is attached to the rear of the battery box on a 78 gs550. In the picture below, it is the shiny silver box in the middle with only a yellow and black wire coming out of it.

What is the name of this and what purpose does it serve? When I bought the bike the black wire (I assume ground) was not connected. If I connect it to a ground, smoke and a little flame would come out of the box when I revved up.

I appreciate any info.

[Anonymous]

anyone?

[Hoomgar]

I would have replied if I knew but I didn't because I am clueless. I was hoping someone knew for you. It looks to be some sort of condenser or something but is in the wrong place for that. As best I can tell or guess it is your regulator.

[focus frenzy]

thats got me stumped also, I have wiring diagrams for all the 850 and up shafties and nothing like it was used on any of them.

I do know that the early GS1000's had a turnsignal warning beeper that sounded when the turnsignals were on (before the self canceling feature)
I wonder if it was also used on 550's and if that is what it is.

hopefully a 550 owner with wiring diagrams will chime in soon.

[Hotblack]

I would tend to think that siver box is a regulator, which works with a rectifier (which usually has fins on it). Smoke coming out of it when you rev the engine means it can't regulate the stator output, and it's time to pay attention to your charging system. At least your stator isn't cooked (yet). I recommend that you read The Stator Papers on the main website.

The other parts are the fuse block (bottom left) the starter relay (top left) and I believe the box for the main fuse (top right).

[Anonymous]

Well it's broken now whatever it was. Check your battery voltage at high RPMs, you don't want to see anything in the 15 Volt range.

Steve

[focus frenzy]

DOH!!!
I dont know why I didn't think of it earlyer, I went and looked at the parts diagrams on bike bandit and now know what the bugger is!!!!
it is the voltage regulator and by having fire and smoke coming from it, it is safe to say it is cooked.
it flames up when you rev the engine due to the fact that the power output of the stator increases with speed and the regulator regulates this output by sending excess power to ground.
but yours is bad.
are you thinking about biding on the electrical parts on E-bay (that is where you got the picture!) or are you the person selling the parts?

[saaz]

I have a 78 GS1000. I have a separate regulator and rectifier. My regulator is finned, similar to the rectifier. It is odd that the 550 has such a different part.

[focus frenzy]

I have a 78 GS1000. I have a separate regulator and rectifier. My regulator is finned, similar to the rectifier. It is odd that the 550 has such a different part.

that is what threw me at first, I am used to seeing them made out of cast aluminum and having fins, but in the diagram on bike bandit, it shows the regulator on the 550 as being steel and smooth.

[Hoomgar]

That's what I did Leon when I suggested it was his regulator in my post above. But the part on bike bandit was not and exact match so I wasn't 100% on it. But I figured, what else could it be?

[Anonymous]

Newbees input

I know I'm a newbee here but isn't that actualy the starter motor cap? The diagrams I see for 78 550's has a finned r/r. The r/r is item 17 and the starter motor cap is item 6. Am I seeing that right? :?

[Hoomgar]

No it has two wires coming out of it and is way too small. But with the way it is shaped I can see how you would think that.

[Hotblack]

I've never seen a 550 regulator, (the one on mine was replaced with a later R/R) and the 750 regulator is a finned aluminum one. All the automotive regulators I've seen were smooth like that one though, with mechanical contacts inside. I suspect the finned ones use electronics instead, like when autos went to a combined R/R housed in the alternator.

[Joe Wolf]

I know this may be a bit late but I have only just started searching through the elecritcal stuff here, my 78 550e has exactly what is descrribed above and I have only been able to find it in the haynes workshop manual diagrams listed as an "output device", as for what it does (i would geuss) I agree that it sends to earth excess current instead of frying your circuit

[earlfor]

It is the voltage regulator. Early model GS's had a separate rectifier and regulator. Later models had a combined regulator/rectifier. Some models had a cast aluminum cover over the regulator and some had a smooth steel stamped cap. Both were used on each model at times depending who the factory was using as a supplier at the time of manufacture. Easiest fix is to replace the burned out regulator and now questionable rectifier with a later one piece unit.

Earl

It is attached to the rear of the battery box on a 78 gs550. In the picture below, it is the shiny silver box in the middle with only a yellow and black wire coming out of it.

What is the name of this and what purpose does it serve? When I bought the bike the black wire (I assume ground) was not connected. If I connect it to a ground, smoke and a little flame would come out of the box when I revved up.

I appreciate any info.