Can rectifier create dead short

[benchrgw]

Out for a great ride this am and with no warning - pop - single backfire and bike dies. Absolutely everything is dead, no headlight, idiot lights, turn signals - nada.

Main fuse and turn signal fuse both blown, I replaced both and still nothing. Now I'm checking battery, 12.58 volts ok, now I check continuity on rectifer and I can find no continuity across any of the connections Red, Red/White, Blue/White and yellow back to the black/white ground wire. I assume this means rectifier is dead, I'm doing this entirely from Haynes Manual so if I'm doing something wrong please feel free to straighten me out. I tested rectifer while off the bike as I took the opportunity to clean all the terminals & connections. I have not reinstalled the rectifier but with battery reconnected now have power again to starter, lights, etc.

Any suggestions on rectifer if that is in fact the case and is their any other way to test other than it should have continuity. I see Z1 has a rectifier listed for $67, anyone had good or bad experience with that and what other problems might have taken rectifer out other than just old age and neglected connections. Thanks as always.

[beerbellykelly]

hi-just gonna guess your bike is a twenty year old at least suzuki-find the wires that come from the alternator [they usually run under the chain-then up to just under the tank]-disconnect them-replace your fuses-start the bike and rev it up when warm to around 3-5000 rpm if the fuses dont blow you have a cooked regulator-the test values given in the HAYNES are lifted from the factory manual-which uses a SUZUKI 'special tester' and will read different to a normal multimeter.

i been fitting honda regulors to my aircooleds for twenty years-there better quality than the suzuki ones and it means another honda dies to give a suzuki life-which always makes me smile.

[benchrgw]

Duh- Sorry it would have been helpful to tell what I was working on - it's a '79 GS1000 E.

[Steve]

The answer to your question is...YES. But not usually.

In order to check the r/r, all 5 wires need to be disconnected. Here is a quote from me on a previous post on how to check the diodes in the rectifier.

Does your multimeter have a "diode test" function on it? It makes a difference. Sometimes just checking the resisitance will work, but a diode test function will actually put out enough voltage to turn on a diode to check it. Please also note that these checks are to be done with the regulator unplugged from the bike. It does not have to be removed, just unplugged.

I have not looked at the exact wording of the test you are trying to do, but the concept is to put one color lead (let's say RED for this test) on the red output wire, and the other lead on each of the three yellow input wires. You should get about the same reading for each leg, and it should show a very high (basically infinite or "OL") reading. Now put the BLACK lead on the red output wire and do the same test. Again, you should get similar readings, but they should show about .5 volts.

Now do the same tests, but put the BLACK meter lead on the black ground wire from the regulator and the RED meter lead to each of the three yellow input wires. With the black meter lead on the black wire, readings will be high, with the red meter lead on the black wire, readings will be about .5 volts.

When it is all checked out, make sure the black lead from the regualtor had a GOOD ground. Don't just bolt it down to the regulator mount, run another wire from that mount up to the battery. When the regulator is trying to regulate, it shunts the excess current to ground, so it needs a GOOD path to follow.

If none of this checks out, contact your source for the regulator to see if there was any warranty. If not, you can spend the money for another new one, or take your chances on a used Honda unit from eBay. If you get a good one from eBay, you will be good to go. By the way, I have not gotten a bad one yet, and I have bought 4 or 5 for various bikes.

[benchrgw]

Steve thanks for your answer - the r/r I see in a number of threads sounds like a one piece regulator and rectifier while the '79 came with a seperate regulator and seperate rectifier. Since my original post I have now found a continuity reading when checking with my multimeter when set on 20M Ohm scale across all 4 wires when tested back to earth/ground. When the backfire occurred this morning I was at pretty low RPM's so not sure I would have / could have caused overcurrent to blow the fuses through the regulator but . Seemed odd that I lost both main and turn signals fuses at the same time. Any thoughts - no obvious burnt wires near the headlight loom, only recent wiring change was I reconnected my fuel gauge last week after installing new petcock and cleaning the sending unit but I don't see a common on the gauge back to the turn signals. Gauge actually was working pretty well, as well as those gauges worked. I never found them to be very accurate particularly going down the road as you get a lot of float bounce. Any other thoughts you might have would be very much appreciated.
Thanks.

[Steve]

Benchrgw,

I sent you a PM.

.