80 to 84 regulator / rectifier

[Superjet]

Good day.....well bad day really. My reg/rect failed its test. No magnetic field at rotor/stator area, no voltage at brushes and continuity test failed on device itself. What have most be buying/ building for a replacement? I have read a few posts about a VR 38 and radio shack 3ph rectifiers. Is this the route most have taken? Your wisdom is appreciated.

Ohh my bike is an 83 with stock ignition and charging. New Shorai lithium battery and new rotor with 4.7 ohms. Stator has 0.8 and all white leads if that helps. New wiring all around the bike with LED headlight tail light but regular turn signals. All grounds are good and sound.

 

[5twins]

Yes, an automotive regulator and a rectifier from the electronics world are the way to go. I've not heard of the VR38 and looking it up, it seems rather expensive. There are many you can use, it just needs to be a ground switching type A regulator (for the '80-'84 system). This Fiat unit is very reasonably priced (and the proper type) .....

https://www.ebay.com/itm/VR794-1979...ash=item1c6f7114ab:g:6pYAAMXQI5tRgJsi&vxp=mtr

For the 3 phase rectifiers, most are either getting them off eBay or from this wind power place .....

https://www.windynation.com/rectifier

There have been a few reports of problems with the cheaper Chinese rectifiers off eBay, but others also report no problems with them. I've never seen a complaint about the Windy Nation rectifiers. Personally, I've been running one for going on 5 years now.

 

[Superjet]

Thanks 5twins for the info. I will take a look around to see. I am in NB Canada and that Fiat regulator is near $50 shipping...Do you have a wiring diagram to put both together? From what I understand thru rectifier to turn ac to dc then thru regulator to smooth out. Am i understanding this correctly?

 

[Paul Sutton]

A good way to search for this Fiat regulator is to use the Fiat Part Number which is 4475112. Type this into Ebay and you will find prices ranging from Chinese manufactured at about £6 up to £20 for Italian and German manufactured. In Europe the mid range item is at about £14 and manufactured by HC-Cargo. There are other regulators that will do the trick but this Fiat one is a very convenient package size. Also, the Heat sink can be bolted directly to the heat sink.

The alternator supplies 3phase AC to the rectifier which outputs a fairly smooth DC current. The beauty of 3phase is it gives a nice smooth DC current when rectified without the need for smoothing circuitry. The function of the regulator is to sense the voltage coming out of the rectifier and then increase or decrease the current to the alternators field winding so that the DC voltage stays very close to 14.5V which is a good voltage level for efficient charging of lead cell batteries. A higher current to the field winding makes for a stronger magnetic field and a higher 3phase voltage. A lower current to the field winding gives a lower output voltage from the alternator. The regulator is constantly monitoring the DC voltage and then matching the field winding current to ensure a stable 14.5V DC is produced.

 

[5twins]

I find my voltage output drops off slightly once the battery has been replenished after electric starting. This usually takes about 10 minutes of riding. We're not talking much, maybe a half a volt, but it does drop. I figure this is normal and just part of the regulator doing it's "regulating" job.

You have a combined reg/rec unit on your bike but it doesn't have to be that way. The '79 and older 650s had separate units mounted in different locations. The plug in your wiring harness for the old combined reg/rec does make it convenient to mount the new separate units next to each other, but like I said, it doesn't have to be that way. Put them where they'll fit best.

If you look at the harness plug for the original combined reg/rec unit, you'll see it has 7 wires. The black is a ground and is shared by both the reg and rec. The 3 whites and the red run to the rectifier. The green and the brown run to the regulator.

 

[XSLeo]

This is the first time I found a reference to that Fiat regulator. Just looked at the E-Bay link, very nice price, I may buy a few for spares.
From looking at the diagram of the regulator, it has a red wire that goes to battery +. On our XS650's you would hook this to the brown wire in your stock reg/rec plug. The green wire would hook to the green wire in your reg/rec plug. The case is ground so you would need a good ground connection on the case, either bolted right to the frame or run a wire from under a mount bolt to the frame or battery negative.
On the 3 phase rectifier there are 5 terminals. three are marked with wavy lines, these are the AC side, these are where the three white wires hook too. The other two terminals are the DC side, one goes to battery positive, the other to ground.
You can cut the plug off your old reg/rec to wire too the new parts. Mount the new parts on a small piece of aluminum that can bolt on where the 80 up stock reg/rec does. Just match the wire colors out of the plug to the new reg and rec. This makes it pretty much plug and play.
Leo

 

[5twins]

Yes, the Fiat regulator is a nice little unit, smaller and more compact than the other "tin box" types. Looks cool too, lol. And it appears we're not the only ones to have discovered this little gem. These guys look to be using them on their combo reg/rec units, and getting near $150 for them .....

http://www.oregonmotorcycleparts.com/Reg_rec_units.html

Since the regulator can be had for $10 or less, that's an awful lot to be paying for a few wires, a couple plugs, a mounting plate, and a rectifier. But, I guess people don't know any better.

 

[Superjet]

Thanks guys. I knew i would get answers I can count on. My bike is far from stock. The bike was done up poorly by another person. It has been an interesting 3 months of wrenching for sure. But had practice with my 77 i had before. It now runs, but lacks charging.

 

[Superjet]

Got the Fiat regulator and Windy nation rectifier on order. Should be here by the end of the month. Thanks guys for the help. Very grateful.

 

[TwoManyXS1Bs]

... no voltage at brushes...

Ohh my bike is an 83 with stock ignition and charging.
...new rotor with 4.7 ohms...

80-up alternator rotors are grounded by the regulator,
By way of the outside brush.
Power is supplied to the inner brush.

No voltage at inner brush, means to check power delivery from brown wire...

 

[xjwmx]

Here's the best '80+-ish diagram. Been very valuable to me.

 

[Superjet]

Thanks for the wiring diagram but it doesnt match up to the one I got. The manual I got is for an SJ. Main difference from what I saw was red going from battery to switch/ and 20a fuse and to reg/rec. My diagram has from battery to 20a fuse to red at reg rec then to switch. Is this the same?

 

[fredintoon]

Thanks guys. I knew i would get answers I can count on. My bike is far from stock. The bike was done up poorly by another person. It has been an interesting 3 months of wrenching for sure. But had practice with my 77 i had before. It now runs, but lacks charging. View attachment 116632 View attachment 116633

Hi Superjet,
hopefully the Fiat parts will get your '83 bike charging again.
As you say, it's "far from stock" and the photo shows it lacks a front fender.
Which is OK if you like the look but the XS650 stock front fender is also a fork brace
and the stock forks need all the help they can get.
An aftermarket fork brace should be on your shopping list. And a front brake lever
with a smaller diameter piston will improve the brakes.
Your '77's photo solves a mystery for me, seeing as it's tank has the same paint job
as my '84 Heritage Special's tank

Which is likely why I couldn't find a Black/Burgundy paint spec for it in the literature
and is another proof they built up the last of the XS650s from whatever parts they
had left over in the warehouse.

 

[Superjet]

Fredintoon I do have the front fender that I will be cut up to shorten the front and rear of it. If I dont put on, a fork brace will take its place for sure. My 77 had been a mix of parts from various years. The tank was purchased from a guy building a bobber. It was like new and so was the bike before a bad hack job. As for brakes I purchased the wrong master cylinder 14mm bore for a single caliper. I will run it for now and see how it does. From what i remember it was the same bore on my 77 and i didnt have any issues. Later will be 12mm and I also have a Brembo kit to install later. I was on a budget for getting my 83 back running, driving and stopping. So far I left out charging...lol

 

[5twins]

Yes, there is a mistake on that colored wiring diagram. The red wire from the battery should run only to the 20 amp fuse. The branch off to the ignition switch should be on the red wire out of (after) the fuse.

 

[xjwmx]

Yep, and it has the audacity to be named "fixed". Fixing it for real would be extending that one trace from the igntion to the other side of the fuse and then covering over the original connection. Don't know what to name it though... It's uniquely easy to read and useful aside from that relatively minor problem.

 

[Superjet]

Thanks 5twins for the clarification. I wired it up based on my diagram not the one attached above. XJ it is nice seeing the color coded diagram....as long as it is correct lol

 

[5twins]

I would have to call that an '80 SG diagram only. In '81, a clutch switch and relay were added, which I don't see on that diagram.

 

[xjwmx]

Superjet, I didn't say it was flawless -- I said it was the best It will substantially apply to all years with ei and r/r.

 

[650Skull]

Caution, just about all diagrams have some mistake in them. If i know of it i will try to change it or i will make reference to the mistake.
I do not know of, or looked for mistakes in this diagram.

82SJ/83SK