What Electrical Parts to Replace

[xjwmx]

So Pete, back to my original questions. Where is the second hole for use with '80+, and does it get hot enough to really need the heatsink compound (it will wash out quickly). Don't answer me and I will call it half-finished again

 

[pamcopete]

xjwmx,

Here is a picture of the complete assembly as I was installing it in my '81/H three years ago. The noted changes were done before final installation:

The two mounting holes line up with the stock threaded holes on the center frame. The upper cut corner was to clear the left side cover and the lower cut to clear the swing arm. (Edits)

The rectifier that is wired to two of the white wires from the stator draws about 12 Amps under full load conditions. The drop across the diodes is about 1.2 volts, so that is about 14 Watts for each wire. In such a small surface area, it does get hot, but it is well within the spec for the rectifier, which is 25 Amps. These are estimates, and you may come up with a more exact figure, but suffice to say the rectifier gets hot and has to be heat sinked.

Do I want to discuss what is meant by hot, a relative and subjective term? No.

Do I want to discuss the theory of heat sinks and what size heat sink would be optimum for this application? No.

I used the heat sink compound from Radio Shack. Heat sink compound does not run. It tends to solidify.

Do I want to discuss whether or not the heat sink compound runs when it gets hot? No.

This setup has run on my '81/H for three years with no problem. I have the same rectifier setup on my '78/E for 10 years. I have no idea what you consider to be reliable, but in my world, that's reliable.

If you look closely at the bottom rectifier you will notice that one set of diodes is not used and is available as a spare should any of the others short out.

Here is a picture of it installed in my '81/H:

 

[SICKLEBOY]

Thanks for the tips , I'm just starting on a complete build up ( less the motor I hope lol)
and I need as many tips as possible !
This is something I think just about anybody could tackle and cheap enough to make as an extra...anything else to know about wiring a bobber/chopper?

 

[xjwmx]

xjwmx,

Do I want to discuss what is meant by hot, a relative and subjective term? No.

Do I want to discuss the theory of heat sinks and what size heat sink would be optimum for this application? No.

Do I want to discuss whether or not the heat sink compound runs when it gets hot? No.

Sounds like it heat up a little.

 

[Tech7]

Hopefully Pete will see this and help me out. I want to do this conversion, but have a couple questions. I assume the nylon screws are being used because the Chrysler regulator is regulating the ground side, so my rotor is reversed. Correct? That's not a big deal anyway. My other question, somewhat related is, what is the resistance spec across the terminals for the rotor. I saw on the Curly link it was 5-5.5 ohms, but I thought I saw another post saying something different. I just want to check my rotor and stator and make everything all right. I appreciate the advice.

 

[pamcopete]

Tech7,

That's one way of looking at it. The Chrysler reg does provide a chopped ground on the green wire, so you have to have battery on the other brush, which is grounded in pre '80 models.

Curly is right. Best to remove the brushes when doing the measurement with your Ohm Meter to eliminate any out side influences, and to eliminate the resistance of the brushes and the crud on the slip rings.

 

[Tech7]

That's what I thought. Just picked up the rectifiers at Radio shack. $3.29, such a deal! Unfortunately, my rotors measuring at about 2.5 ohms. I kinda figured that, as I full fielded it, and only would charge 13 volts at higher RPM's. Whatever, it's 30 years old, right?. So, tomorrow , I'll check my stator, order a rotor, and start building my reg/rect. I really appreciate your quick response. Your the best. BTW, I remember reading some time ago about some bad rotors going around. Any I should avoid? I guess tomorrow I'll ride the Zook.

 

[pamcopete]

Tech,

Avoid all rotors except for Custom Rewind rotors from Gary in Birmingham, AL 800 798 7282

Gary is the best. You can pay more, you can pay less, but you won't get any better.

$125 rebuild plus your core. He often has a rotor puller to lend out as well. Do not even think about removing the rotor without the proper rotor puller, also available at Mikes.

Replacing the rectifier will prolong the life of the rotor, or, having an old rectifier will shorten the life of the rotor because of the losses across the diodes in the rectifier make the alternator have to produce a higher voltage and that means more current flow in the rotor and more heat, which fries the rotor.

 

[Tech7]

Thanks again brother

 

[79xs650rider]

Hey guys thought I'll throw this out there too.. I just bought the chrysler regulator from napa and they told me it had a lifetime warrenty on it...been seeing alot of them saying a year...but a lifetime is better....just sharing some info they told me..JD

 

[pamcopete]

79xs....,

Well, that is significant. Buy and install a Chrysler regulator from NAPA and it will be the last one you ever have to buy, and only $14.99. The companion Radio Shack rectifiers are more than adequate for this application, so they should last forever as well.

NAPA part # MPEVR38SB

 

[rodemyyamaha]

Hey Pete. Where do I get the nylon screws? Been delayed by job hunting but now back on track and ready to finish this baby.
Thanks for all of your valuable info.

 

[pamcopete]

rode.....,

PM me for the screws.

 

[Capt_Zoom]

first...super writup for the pre '80 models...you got my '77 set when I get to that build.

But what about the '80+ models. What would you replace there (FYI: I'm running the stock E-ignition). Would the same components from napa and radio shack work Are the stock one's better on the '80+ models or should I also change those as well? If so is it simplier since the wiring is closer? If I'm understanding this thread right, I think they would but are there any install differences like the nylon screws?

Thanks and sorry about all the questions.

 

[kent_in_kc]

xjwmx, Dude - chill. You're being rude. The man's trying to help out another fellow and you hijacked in and started howling. Not cool. And you're wrong, by the way.

 

[XSLeo]

Capt Zoom, yes the 80+ models don't need the three nylon screws. The 80+ models combo reg/rec work without a grounded brush.

 

[guyf2000]

Pete:
A bit late on the thread but thanks for developing and posting your work. Was looking for a fix for another vehicle using the Chrysler dual field regulator. The thread came up in the search, and I happen to have a couple 650s waiting their turn in "getting things going again".

Pics are good; I understand the electrical bits, but attaching lumps to other bits without creating a kluge is not one of my strong points.

 

[gapper]

So is there a specific rectifier that I must get? Also does the wire harness come with the crysler regular? I have tested mine and I get no continuity on it so I figure that it is done. So I can just mount all three items on a aluminum sheet and bolt it to the frame then, from what I read and see.

 

[retiredgentleman]

gapper;

As you may know, Radio Shack has left Canada. I looked around at the electronics outlets here in Calgary and found bridge rectifiers at "Active Electronics". I bought 2 of the NTE 5326 single phase bridge rectifiers. They are rated at 25 amps each and cost $5.99 each.

Shop around locally where you live or you could try on line. Maybe Radio Shack will ship from the USA?? Places such as Mouser.com sell everything, but might get expensive with shipping/handling etc.

 

[xjwmx]

xjwmx, Dude - chill. You're being rude. The man's trying to help out another fellow and you hijacked in and started howling. Not cool. And you're wrong, by the way.

Ha. I finally saw this. I wasn't being rude to anyone. I had and still have the same questions about it. Ignoring those questions, or making light of them, is rude. But we play favorites here.