solid state rectifier on the cheap

[mgunner]

-79' xs650 special-

alright i've almost got the electrical system renewed on a friends bike with a new harness and a few odds and ends. but i went to re-attach the rectifier and found the ground wire (black) is completely gone for whatever reason, but it looks like it burnt away from the looks of it.

Ive been shopping around and the prices i've found range from 50.00 for stock to about 100.00-150.00 for a conversion to a R&R.

but i also found an interesting article here:

www.xs650.org.au/xs650%20tips.html#$20%20Rectifier

under "20 dollar rectifier" it mentions that these were basically modified versions of what can be found here for about 25.00:

www.autozone.com/autozone/catalog/oems/oemsProduct.jsp?counter=0&categoryDisplayName=Starting+%26+Charging&fromString=search&itemIdentifier=45074_0_0_&productId=45074&sortType=&parentId=64-0&filterByKeyWord=94021546&navValue=16400225&categoryNValue=16499999&itemId=225-0&displayName=Alternator+Diode&store=678&oemPartNumber=94021546&brandName=Duralast

my question is has anyone tried this before and how different was the wiring and mounting for it? I would much rather pick this up at my local autozone for a quarter of the price, than buy a new one.

[XS Rod]

mgunner,
Check the diodes with a multimeter... if it checks out OK, solder the wire back on and run it.

[pamcopete]

This message was deleted by the original poster.

[weekendrider]

mgunner, is this coyotewackers bike?

[pamcopete]

Here is a suggested replacement for the rectifier on 1970 to 1979 XS650's. Go to Radio Shack and buy 2 #276 - 1185 Full Wave Bridge Rectifiers for $3.29 ea.. Wire and mount them as follows:

1. Fabricate an aluminum plate approx 3 X 2 inches. Use .125 aluminum. This is the heat sink.
2. Mount the Rectifiers per the drawing, using heat sink compound between the bottom of the rectifiers and the plate.
3. Solder wires per the diagram.
4. Recommend that you eliminate the plug and connector as they are toast and you have to solder anyway.
5. Solder the wires from the Rectifiers per the diagram to the existing white wires going to the Alternator and plus / minus (Red / Black).
6. Use a heat sink when soldering the wires to the rectifiers.
7. Mount this assembly in the same place as the original, using either the center hole (as shown) or one of the mounting holes for one of the rectifiers.
8. Note: Do not ground the black wire on the mounting screws. The battery box is floating, it is not a ground.

The Radio Shack rectifier is rated at 25 amps. Two of the three white wires go to one rectifier and the other one goes to the other rectifier, so about 10 amps max is going through one rectifier at full load, with the remainder, 5 amps, going through the other.



The "N/C" terminal can be used as a spare in case one of the diodes shorts out in the future. You could "pre solder" a short wire to it so if you have to use it you can just cut and splice the affected white wire to it.....don't even need a soldering iron!

Life is simple: Ride. Enjoy.

[pamcopete]

Here is a replacement for the regulator:

This regulator requires you to modify the connections on the brushes of your alternator to work like the brushes on a '80 to '84 model.

1. Got to www.partsamerica.com or your local NAPA store.
2. Search for part # AL154CS @ $17.99 or VR295 or NAPA MPEVR38SB $16.69
3. Remove the ground connection from the inner brush.
4. Replace the three screws on the brush holder with nylon (not plastic) screws (M4-12)
5. Run a wire with a 7.5A inline fuse from the now isolated brush to a source of +12 volts from the ign switch (brown wire)
6. Install and wire the regulator as shown. The wire connections to the regulator use female bullet terminals.
7. The regulator does not have a ground wire. You must ensure that the case of the regulator is grounded. The battery box, where the stock regulator mounts, floats on its rubber mountings and is not a ground.



In the process of testing this setup for the '80 to '84 models I modified my bike as above and installed the regulator. Works the same as the VR291.

This regulator was used on virtually all Chrysler products from 1970 to 1989. It supplies a regulated ground on the green wire to the rotor brush instead of battery so if the rotor shorts out to ground it will not fry the regulator or blow the main fuse. I like it because it is technology from the same era as my '78 XS650 and it's available everywhere for a very low cost, not because it's a cheap product, but because there are lots of them out there and the auto stores are interested in selling them. Advance offers a one year warranty.

The wire connections to the regulator use female bullet connections, but you should remove the protective plastic from the connections for better contact.
Note: Also available from NAPA as their part number MPEVR38SB for $16.69 or from your local "retired vehicle" yard for $5.

[mgunner]

weekendrider: nope, don't know the guy lol

and holy crap pete, thanks for all that. i think i will definitely go that route with both the regulator and rectifier now, thanks a ton.

but as long as your on here, this bike happens to have one of your ignition systems to replace the stock points and I was worried that whatever happened to the harness might of effected the system. (more or less im trying single things out as i go)

How would i go about testing your system to make sure its still functional?

He also bought this i think a little over a year ago and didn't touch it after, until i got a hold of it now.


Side note: it also has a "green monster" ignition coil (basically a dyna coil?) do you know how i could also test this, besides seeing if it throws a spark.

thanks guys.

[pamcopete]

mgunner,

Well, you can measure the resistance of the coil:

Primary: 3.3 Ohms
Secondary: 23K Ohms from plug cap to cap. (5K Caps)
Primary to secondary: Infinite on highest Ohm meter range
Primary or secondary to core: Infinite on highest Ohm meter range

CAUTION: The "Green Monster" coil (17-6810) will arc internally and fry itself if you apply power with one or both spark plug wires disconnected from their respective plugs.

Then, you can use this procedure to test the PAMCO and the coil:

1. Use a voltmeter and check for battery voltage on each of the red/white wires with the key and kill switch are turned on.
2. The dual output coil has to have both spark plug wires connected to a spark plug at all times.
3. To test for spark, connect one of the spark plug wires to a spark plug that is grounded to the engine.

To test for spark without having to turn the engine over, do this procedure:
1. Remove the PAMCO rotor.
2. Remove the locating pin in the advance rod.
3. Reinstall the rotor, but without the pin.
4. Replace the nut holding the rotor on loosely. This will allow you to spin the rotor to produce a spark without having to turn the engine over.
5. Connect one of the spark plug wires to a spark plug that is grounded to the engine, but not installed in the engine.
6. Make sure that the other spark plug wire is connected to a spark plug in the engine.
7. Turn on the ignition switch and the kill switch.
8. Spin the rotor while looking at the gap in the spark plug for a spark.
9. Turn off the kill switch and the ignition switch.

Let me know if you have trouble finding the nylon screws for the brush mod. I have a bunch here and I'll send you a few. Or, you can go to www.smallparts.com

If you go with the regulator mod, keep your receipt because the regulator is warranted by the store.

[mgunner]

Thanks again for all your help, this will for sure be helpful. When i get these things built and bought i'll let you know how that goes, and as i get some testing done i'll pop back on here and post as well.



If interested at all, i am an electrical controls drafter and have recently redrew in AutoCAD the wiring diagram for this bike completely and will be posting it up on here shortly (since all i can ever find is the manual scans or sketches). i figure it might help a few people out.
I finished it today, but i have to confirm some wire colors in the switches before i'll post.

Thanks again.

[pamcopete]

mgunner,

There will be a lot of interest in that autocad wiring diagram. If you could export a *.dxf file, that would be great so we can bring it into Word as a picture.

If you do not have a way to post it here as a downloadable file, I could make it available from my hosting site.

[mgunner]

i didn't get a chance to confirm the wire colors in the switches yet or confirm the wiring for the fuse box is correct, I also need to create a color code for it since i made the wires there respective colors rather than labeling them.

unfortunately (ironically enough) work has picked up again for me so im not sure how much time in the next few days i'll be able to put toward this.

i can export to .dxf if that is the format preferred but to make it easier on most i could make it either a .jpeg or .pdf for viewing since these are a more common file type. i haven't figured out how to upload a file to these forums, but i would be fine sending it you to host on your site.

[mgunner]

I have sent you an email Pete, let me know if that's something you would be willing to look into, otherwise this will be up as noted.

[speedfourjoe]

May 18, 2010 13:38:40 GMT -5 pamcopete said:

3. Remove the ground connection from the inner brush.
4. Replace the three screws on the brush holder with nylon (not plastic) screws (M4-12)
5. Run a wire with a 7.5A inline fuse from the now isolated brush to a source of +12 volts from the ign switch (brown wire)

I'm doing the Chrysler regulator/Radio Shack rectifier mod on a '75, and found this thread doing a search. I've got the nylon screws, but have a question. Is the wire I'm pointing to in the picture the ground connection in step #3? Can I use it to run to switched 12 volt if I cut it and splice before it goes to ground on the bike? 

[grizld1]

Yes, the brush with the L-shaped bracket is the grounded brush. The brush will be grounded to the motor unless you insulate it with nylon fasteners or cut the stator case for an 80-and-after the brush holder; otherwise when you connect the black brush wire to switched power you'll achieve nothing but a hard short and a blown fuse.

[speedfourjoe]

Mar 9, 2013 23:29:57 GMT -5 grizld1 said:

Yes, the brush with the L-shaped bracket is the grounded brush. The brush will be grounded to the motor unless you insulate it with nylon fasteners or cut the rotor case for an 80-and-after the brush holder; otherwise when you connect the black brush wire to switched power you'll achieve nothing but a hard short and a blown fuse.

I'm all set to go then. Thanks!