Rectifier/Regulator swap?

[Furious D]

It looks like I will need a rectifier/regulator unit for my 81 special. after replacing the stator and rotor it still wont charge but after checking all the connections I am 99% positive its the rectifier/regulator combo. I dont want to spend a bunch a money since I plan to upgrade to PMA in the future, Right now I just want a cheap fix to get this project rolling.


A quick look on Ebay did not come up with a cheap ones for a 650 but there are several for other Yamaha's like Seca's and other XS's like 750's and such.


Anyone know if they willl interchange? I'm guessing they will as long as the voltages from the stator on the other models is close.

 

[XSLeo]

The one off my 82 Seca 650 is almost the same, the wires are longer.
The thing you need to besure of is if the donor bike has a feild excited alternator or a PMA. I think most of the street Yamaha's of that era used a FEA.
The way to tell is to look in a parts fiche on the possible donor and look to see if the alternator has a feild coil in the alternator. These have a stator mounted out side of a rotor. A PMA has the rotor out side the stator.
Some use brushes, some don't.
Leo

 

[Dennis]

maybe the chrysler configuration might help

 

[XSLeo]

Yes, the Chrysler reg mod will work. That takes a bit of wiring, the Yamaha regs are just plug and play.
I've done a bit of checking and the Xs 750, 850, 1100 all use a Feild Excited Alternator. The Secas did, the Virago's didn't.
So if you can find one from any of these bikes then it should work.
Leo

 

[XSLeo]

I was just on Ebay and they list several for 80-82 XJ 650 and 750's for around $25 with shipping.
I just put Yamaha voltage regulator in the search engine, click the ctagory of lowest price and shipping, in the upper right. On the left, motorcycle, used then scrolled through till I saw ones that looked right. Saw the XJ regs and checked the parts fiche and they have the feild coil so sgould just plug and play.
Leo

 

[Furious D]

Thanks to all. I decided to go with the Chrysler Regulator/homemade rectifier setup.

Now I need to fiqure out where I want to mount it. I was thinking about removing the toolbox and putting it there.

 

[XSLeo]

If you make the plate big enough to mount the reg to as well as the rectifiers then just drill holes in the plate and mount it right where the stock one was.
Leo