regulator blowing main fuse

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corkypromo

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Hi all,

I have been working on some non-charging issues. My rotor tested bad so I just replaced it with a brand new one. Now the main fuse is blowing every time I turn the key on. I tested the source of the short by removing all other fuses and unplugging the voltage regulator. Everything is cool until I plug the voltage regulator back in. That is what is causing the main fuse to pop. Is it safe to say that the regulator is the problem?

The connection running to the stator isn't pretty. It has melted a bit. would a short there cause this?

Just trying to decide whether to buy mikesxs regulator/rectifier, or to tinker a bit more and replace the regulator with the radio shack option or the chrysler.

thoughts?

BTW - it is a '78 special with points.
 
If it's a 78 with the original regulator if it were me I would replace it for peace of mind. In my Clymer on page 38 it gives some regulator test like checking to see if the points are welded together. The voltage checks it tells to do would be kind of hard to do it it blows the fuse immediately. And yes if the stator wiring is suspect it could also cause a short and blow the fuse. The Chrysler option I think is quite a bit cheaper that Mikes isn't it? I think you could charge the battery and unplug the regulator. Start the bike and check to see what the charging system is putting out if you haven't . If I recall at 2500 rpms it should put out 14.5-15 VDC
 
thanks pumps - yea, was just thinking the mikesxs would cover the regulator too. hell, at that point almost the whole system would be new (minus the stator). is there a quick test for the regulator?

I'm gonna replace the stator connector and see if I'm still blowing fuses.
 
Doing the Chrysler mod is easy. A RS RZ ZR one of thise followed by a 292. Is the regulator I'm using. Ask for a 75 Dodge Dart with a slant six engine. They will give you the right one. You give them $17 Or there abouts. Remove the stock regulator. Cut the plug off the stock regulator as close to the regulator as possible. You will have a Brown a green and a black wire. You may need to extend the wires a bit. On the regulator you will see a triangle shaped hole with two pins in it. The upper left pin hooks to the green wire. The lower center pin hooks to the brown wire. The case hooks to the black wire.
Now down at the brushes you need to replace the metal screws on the brush with the black wire with nylon screws, not plastic, plastic melts. If you can't find them local a guy on ebay is selling them four for a few bucks. Don'y recall exactly.
Now at the big plug in where the stator wires plug into the harness a few inches up in the harness cut the black wire off. This black wire needs to hook to the brown wire at the regulator.
It sounds harder than it is. I did this on my 75 and it's great.
Doing the rectifier mod takes a bit off building. You need a couple Radio Shack Bridge rectifiers #276-1185 $3.29 each. A small piece of 1/8 inch thick 3x3 inch Aluminum. Some wire and bolts, solder and a bit of time to assemble the parts and hook it to the bike. I did it all for less than $30 bucks. If you want to read more about it, then you can go to the Garage and read all about it. There may be links in tech section on this site.
Even if you use the more expencive regulator, at about $40 it's still half what Mike's sells and come with a year warranty.
With everything It cost about
 
just wanted to check back in with SOME progress...replaced the regulator with 292 solid state. Started up the bike and the voltage is really hard to ready. It is jumping from 12-13.4 or so at idle. It actually is a bit lower when I rev the engine. So, it seems my problems are not over. Radio Shack rectifier is up next.
 
oh, one other odd thing. my headlight and dash lights always (for years) came on as soon as the bike was running, now the lights "on-off" switch actually works. weird!
 
That is the same unit as the starter relay, right? I always kick (bendix still needs replaced) it so, I wouldn't have even noticed if it went.
 
Last edited:
corkypromo,

Whenever I encounter a problem, I always start looking in the area of where I did my last repair or mod, because it is most likely that some sort of mistake may have occurred there.

In your case, I would suggest looking at the positive brush holder and wire to see if perhaps you inadvertently shorted the brush to ground. A problem with the rectifier would not cause a fuse to blow when you plugged in the regulator. The regulator just provides power to the rotor. It's also possible that your new rotor is also at fault, so I would go back to the rotor and brushes.
 
+1 that the most likely cause of the problem stares at me with blood shot eyes each morning.
 
The safety relay is NOT the starter relay. The safety relay is a relay that turns the starter off as the engine starts and turns the headlight on. It gets power on the yellow wire from the stator.
 
thanks guys.

yes, pete. I think I may have shorted the brushes but didn't realize it til I went to start the bike. Engine didn't want to turn...the stator wasn't seated properly. I did hit the electric start while trying to figure out why the motor didn't want to turn which is probably why the relay is toast.

I'm kind of doing more harm than good.

but, now I don't think I have any shorts in the charging circuit. she still isn't charging correctly, so I'm working on building the Radio Shack rectifier and I guess I need to find a new safety relay.
 
corkypromo,

Well, I don't see how hitting the electric start would fry the safety relay. I think you mean the starter relay / solenoid?
 
took me forever, but I have the charging issue resolved! Thanks to all of you!

I did the radio shack rectifier, jeep regulator, and I replaced the rotor and stator. The safety relay wasn't an issue...once I got the charging system right that worked fine. Just got back from a ride and everything seem good! except for some back firing as I down shift, but maybe I'll start a separate thread for that.

thanks again guys for all of your advice and guidance.
 

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