Nylon screws

Derek, From the look of it your stator is for a 70-79 so that part is ok. On the reg/rec it should be right but I can't say for sure because I don't know the maker or model number so I can't reaserach it to find out how it is set up.
As you follow Curly's/gggGary's charging guide. Follow the early procedure.
Testing the ohms of the rotor and stator are easy to do and will reveal a lot.
77, if you are using the stock 77 reg and rec then no nylon screws are needed. If you use a combo reg/rec then just what one and how it hooks up you may or may not need the nylon screws.
Leo

I finally just threw up my hands and went with a Permanent Magnet Alternator after changing out the rotor, stator, regulator, and rectifier. I just bit the bullet, and bought the PMA from Mikes XS. This ain't my first XS. Always had problems with the charging systems on these bikes, but my current XS (a 78) is the worst I've encountered. After getting the PMA I'll never go back to the piece of crap Yamaha decided to equip all models of this bike with. I love my PMA!

XSLeo said:

On a 73 the stock regulator and the rectifier are seperate units.
Even if you rewire the bike to simplify the harness you won't need the nylon screws if you use the stock reg and rec.
If you are going to rewire everything, it would be a good time to upgrade from that old, unreliable mechanical reg to a solid state reg. Those mechanical regs work, but not very well. Even new the could over charge the battery if you ran at highway speeds much.
The reg that RG shows is a good one. Using that one you won't need the nylon screws either. The solid state unit turns the rotor on and off quicker than the stock mechanical reg. This will help keep the rotor cooler. Cooler = Last longer.
The rec he shows is much more efficient than the stock one. And don't cost much.
You can probably buy the new parts, hook them up and sell the old parts and pay for the new parts.
I know you just asked about the nylon screws, but using the old parts will let you down sooner or later. I would suggest doing the mods now while your down than have to get stuck somewhere and have the long push home.
Leo

Click to expand...

sorry to dig up and old thread but I'm confused by this. I thought this after market solid state regulator would put out a ground signal on the wire going to the brush now as opposed to the 12v going to the brush that the 1973 would be putting out. If this is the case would he now need to swap to nylon bolts so it grounds through the brush? I apologize if im off base Im just trying to wrap my head around everything.

Ok, A quick run down on the 70-79 system. When you turn the key on the regulator reads the voltage on the brown wire. If this voltage is low the reg sends full battery voltage out on the green wire to one brush. from this brush through the rotor, out the other brush. The brush gets grounded to the stator by the mount screws and back into the harness on the black wire. This turns on the system and charges.
On the 80 up key on, power goes to one brush on a brown wire. through the rotor, out other brush on the green wire to the reg/rec.
The brown wire also goes to the reg/rec. The reg/rec reads voltage on the brown wire. If low the reg/rec grounds the green wire. This makes the system charge.
The 80 up don't ground at the brush as the 70-79 do.
If you use a reg/rec designed for the 80 up on an early bike you need to do the three screw mod, which is the three nylon screws plus rewiring the brushes.
Leo

thanks for the break down. I appreciate it. I went to my bike this morning (im storing it at my work as I don't have a garage at my house) and I put a multimeter on the battery, fired the bike up and applied 12v directly to the green wire at the back of the regulator ( had the reg unscrewed and hanging there) and it seemed to just be shorting out. the wire got very hot right away so i stopped. It's a 1977 xs650 i should probably add. I checked with the multimeter and the green wire is definitely a ground. I tried applying 12v directly to the screw at the brush with the stator cover off and it did the same thing. Am i doing something wrong?

Also the charging system isn't doing anything. the battery went dead on me on friday when i was riding it in the parking lot at work (i just bought the bike so i haven't ridden it around town yet im just trying to work the bugs out of it) i charged the battery up and put it in the bike so the multimeter was reading nominal battery voltage (around 12.6v) regardless of how high i revved the bike.

https://imageshack.com/i/12hvjoj brushes

https://imageshack.com/i/0i3ysjj green wire that I jumped 12v to

Your pics don't show up for me. I never had much luck trying to post pics from or looking at pics at imageshack. I find it easier to just upload them straight from my computer.
Unhooking the reg/rec and letting it hang there might not be a good idea. Most ground through the case.
Which one of these pics look like your brushes?
Pic #1 is the 70-79 set up. Notice the wires and where they hook to the brushes. The green hooks under screw #3. The black under #1. Also notice how the inner brush has a long mount that goes from #4 up over the brush, down to #2 then over to #1.
The second pic is an 80 up set up. Notice that there is no black wire. The green is still hooked under screw #3. The other wire is brown and goes over and hooks under screw #2. If you look closely you will see the shape of the brush holder is different. Pic #1 the holder has just one rounded place under a screw and the second has two rounded places under screws. This rounded spot is the insulator so the wires that get hooked under them don't ground out. You will see this better in the second set of pics.
If yours looks like the first pic you jumper from battery positive to the green wire to bypass the reg.
If yours looks like the second pic jumper from the green wire to ground to bypass the reg.
Where do you have your reg/rec mounted? If on the side of the battery box, it won't be grounded. The battery box is supported by rubber mounts. I might suggest that under one of the mount bolts you clean the paint or powder coat off the reg/rec around one of the bolt holes. Now run a wire from this clean bare metal spot to a good clean bare metal spot on the frame. Like where the negative battery cable bolts to the frame.
Leo

ok I think i've managed to attach the pics now. from what I can tell everything is stock. The regulator is mounted to the battery box in what appears to be the stock location. Mine being a 1977 there should be a seperate regulator and rectifier from what I understand but looking at the image that ive attached of my regulator it almost appears to be a combo reg/rec with the 3 white wires on there. I've also attached a pic of what's on the right side of the bike that I thought was the rectifier until i noticed that there isn't 3 white wires going to it. what do you think?

Ok I see your pics. #1 are the brushes typical of the 70-79 bikes.
#2 is the regulator.
$3 and #4 are the safety relay.
The rectifier is bolted to the bottom of the battery box.
I don't know how to link, but if you look through the XS650 TECH section, found near the top of the page and scroll down to electrical you will find a listing for the charging guide. This will take you step by step through trouble shooting the charging system.
Oh just so you know your bike is not bone stock. The header wrap and shorty mufflers are not stock.
Leo

oh right I forgot about the exhaust. I bought it from a friend who needs everything loud

So based on what you're seeing here I should be able to connect 12v to the green wire to bypass my regulator? Any thoughts on why it appears to be short circuiting when i connect the 12v to it? I've tried at the back of the reg and directly at the brush as well...

well after further investigating I removed the green wire from the positive brush and I found that the green wire was still shorting to ground. I unplugged it from the regulator and metered out the section of green wire between the brush (still disconnected) and the disconnected plug at the voltage regulator and it was no longer shorting to ground. So I've isolated the short to be within the regulator. I cut off the harness right at the regulator and i will use it to attach to my new Chrysler reg that i picked up today. Once i had cut the harness away from the reg i checked it again and it is definitely shorted internally so it's got to go. I checked resistance across the rotor as well and there's pretty much none there so that also needs replacing. I'm not sure if the shorted rotor caused the reg to fail but either way they're both in need of replacement.

I also picked up the parts to make the rectifier so I will do that at the same time. I came across another source for the Chrysler regulator that I didn't see listed on this forum during my search. An automotive electrical company called "Wilson" has them. The part number is 62-05-9650 and it's the OEM regulator for a 1975 Jeep Cherokee. I gave various numbers to NAPA and they couldn't make any sense of them but I saw in another thread on this forum a list of cars that these reg's are found on so I just asked the parts guy to look up the reg for a 1975 Jeep Cherokee and it appears to be identical to the other Chrysler regs that people are posting pics of. It cost $37 so that seemed reasonable by Canadian standards

I've attached a photo of it below. Please ignore my wife's super girly planner...

ljevans said:

well after further investigating I removed the green wire from the positive brush and I found that the green wire was still shorting to ground. I unplugged it from the regulator and metered out the section of green wire between the brush (still disconnected) and the disconnected plug at the voltage regulator and it was no longer shorting to ground. So I've isolated the short to be within the regulator. I cut off the harness right at the regulator and i will use it to attach to my new Chrysler reg that i picked up today. Once i had cut the harness away from the reg i checked it again and it is definitely shorted internally so it's got to go. I checked resistance across the rotor as well and there's pretty much none there so that also needs replacing. I'm not sure if the shorted rotor caused the reg to fail but either way they're both in need of replacement.

I also picked up the parts to make the rectifier so I will do that at the same time. I came across another source for the Chrysler regulator that I didn't see listed on this forum during my search. An automotive electrical company called "Wilson" has them. The part number is 62-05-9650 and it's the OEM regulator for a 1975 Jeep Cherokee. I gave various numbers to NAPA and they couldn't make any sense of them but I saw in another thread on this forum a list of cars that these reg's are found on so I just asked the parts guy to look up the reg for a 1975 Jeep Cherokee and it appears to be identical to the other Chrysler regs that people are posting pics of. It cost $37 so that seemed reasonable by Canadian standards

I've attached a photo of it below. Please ignore my wife's super girly planner...

Click to expand...

Yes, if that regulator is for a 1975 Jeep, then it will work quite well for your 1977 XS650.
You should not call that regulator a "Chrysler" regulator, because the "Chrysler" regulator refers to regulators used on 1970's Chrysler cars and trucks, and the electrical connections are opposite to the 1975 Jeep. A "Chrysler" regulator will not work on your 1977 stock alternator.

Resistance from rotor slip ring to slip ring should be around 5 ohms. You did not give an exact number, but if its less than 4 ohms then it must be replaced or rewound.

In case you don't know, the Jeep brand was owned by American Motors in the 1970's. That is why the 72 to 75 Jeeps use the same regulator as the AMC 71 to74 Ambassador, Jevelin, Hornet and Gremlin. In the 1980's Chrysler bought the Jeep brand. In other words, a 75 Jeep regulator is not a Chrysler regulator.

Oh so the VR-115 is not the Chrysler reg? for whatever reason I thought it was. This reg that I have is a VR-115 but I found it under the Wilson part number. So does the VR-115 still send a positive signal down the green wire or a negative one? I was under the impression that I was going to have to isolate the grounded brush when I do this mod? I thought the VR-291 was the same as the VR-115 and I was going to wire it as per the attached diagram.

The rotor had less than 1 ohm of resistance so it's safe to say that she's going to be put out to pasture.

it looks like they're the same so I should be able to still wire them as planned? How do they differ from the chrysler? Based on the info in the attached thread the VR-295 (which i believe to be the actual "chrysler" one also sends a ground signal down the green wire.

http://650rider.com/index.php?name=Forums&file=viewtopic&t=8476

Hmmm...in reading further down that 650 rider thread I see Pamcopete posted:

"If you use the VR291 or VR115 or their equivalents, then no change is required.

If you use the Chysler VR295 or its equivalent, then you wouyld have to do the nylon screw mod to isolate the inner brush from ground"

which I think answers my question that I do NOT have to isolate the grounded brush when using this particular reg. Is there an advantage of using the Chrysler reg over these other regs?

ljevans said:

Oh so the VR-115 is not the Chrysler reg? for whatever reason I thought it was. This reg that I have is a VR-115 but I found it under the Wilson part number. So does the VR-115 still send a positive signal down the green wire or a negative one? I was under the impression that I was going to have to isolate the grounded brush when I do this mod? I thought the VR-291 was the same as the VR-115 and I was going to wire it as per the attached diagram.

The rotor had less than 1 ohm of resistance so it's safe to say that she's going to be put out to pasture.

Click to expand...

Correct, the VR-115 is not a Chrysler regulator. Its an AMC regulator. The VR-115 sends a variable positive voltage down the green wire to the left (outer) brush. The right (inner) brush is grounded to the alternator frame, and also has a black ground wire from the harness. Your stock 1977 alternator brushes do not require any additional isolation such as nylon screws. Yes the VR-291 is equivalent to the VR-115, and the diagram you show is correct.

The green wire from the regulator goes to the left outer brush. Make sure that the regulator black wire goes to a good frame ground. I connected the black reg wire to the existing black common ground wire that runs in the wiring harness. The battery box is not grounded.

Brushes must be 3/8" or longer. Be careful with the screw lengths that mount the brushes. There are 2 lengths, and its possible to cause short circuits if you put the long screws in the wrong place.

Yes, a 1 ohm rotor probably burnt out the old stock regulator. The VR-115 regulator works extremely well on these bikes.................you will like it.

That's great thanks for the info. It's nice not having to isolate the brush. Not a big job but the less mods required the better at this point

The Chrysler reg is less expensive than the AMC reg. The Chrysler reg I used was $13.99 when I got it. The AMC reg was around $35.
I used the three nylon screws at first and it works great. I had an 82 stator of my parts bike so I swapped that for the one on my 75.
The 80 up stators already have the ungrounded brush.
Works great this way too.
Leo

Hi Leo,

So just to be clear you used the nylon screws because you used the chrysler regulator but I won't need them with the AMC regulator?

Thanks.