GL1000 Silicon Rectifier

2906 Views 8 Replies 6 Participants Last post by 2Dahorizon, Jul 27, 2009

The New Owner

Discussion Starter · Jul 24, 2009

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Hi there, as my bike is off awaiting for the new float valves to arrive,today I've done the charging system inspection. The stator seems to be good (all three yellow wires shorted together, none connected to the ground), but when I checked the rectifier as described in the manual I wasn't happy with the results. Resistance between the green and anyyellow and between anyyellow and thered/white in FLOW direction, which should be 5-40 ohms, reads around 430ohms in all the mentionedcases. So the rectifier has gone away, isn't it? Now, I'm not really happy about having to buy a new one, so I was wondering if I could make my own? I guess that shouldn't be a problem, six diodes soldered together tomake a "bridge" as shown inthe service manualsketch and fixed to a heat sink. But I don't know isthat all or there is something more inside,like some terminal to the voltage regulator or something else? And which diodes to use? If anyone knows....

The bike is '77th GL1000, the silicone rectifier and the voltage regulator are separated.

And by the way, I found another catastrophic error in the wiring. Only two of the three phases (yellow wires) from the alternator were going to the rectifier. The third one was going nowhere. Actually, it was going somewhere under the right-hand false tank cover and there it was cut and insulated, while the respektive yellow wire from the rectifier'sconnector was directlyconnected to the headlight switch and its contactwas useless there(though it might have some role while the reserve lighting system was there, removed by the PO). So the charging system had only two phases from the alternator to work with, which was 1/3 of the capacity. And I was wondering why the voltage on the battery will not exceed 12.8V at any RPM. Anyway, I've cut the mentioned third yellowwire thatwas going from the rectifier's connector to the headlight switch and shorted the connector's side of it with the earlier cut wire that was going from the alternator's connector. So now that should be fine.

Now"only" to make a new rectifier.

Thanks chaps!

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ding dong

· #2 · Jul 24, 2009

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Maybe not, on the rectifier being defective.I couldn't check the diodes withmy high dollar Flukedigital meter??? Wouldn't read these diodes correctly, don't know why. Had to use an analog meter to get proper readings.I have checked others with the same results.

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The New Owner

Discussion Starter · #3 · Jul 24, 2009

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Truth my multimeter was quite cheap (bought on a bazaar few years ago) but I never noticed that it reads uncorrectly before....:baffled:butnow I will try to borrow an analogvolt-ohmmeter somewhere and to re check the rectifier. Thanks for the info!

Still, if anyone has a rectifierschematic or something please let me know, just in case that this one is really broken....

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Eagledriver

· #4 · Jul 24, 2009

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Here is how I made a diode rectifier for my 79 Yamaha. I took the diodes from a Delcotron alternator, (60 amp) just one I had laying around in the garage. I made a mounting plate and had some heat sink material, mounted the whole thing under the battery where the other one was mounted. I have checked it many times and it always is running cool, no problems since I installed it about 5 years ago. The alternator on the Yamaha was only 11 Amps so plenty of room to spare on amp rateing. I would think that any diode bridge from a like source would work fine and it sure beat the $144.00 that the dealer wanted for a new one. The bike also has a seperate voltage regulator. I check diodes with my anlog meter and if the diode is good it shows about 3/4 scale. Works for me, good luck on the repairs.

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DaveO430

· #5 · Jul 24, 2009

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Eagledriver wrote:

Here is how I made a diode rectifier for my 79 Yamaha. I took the diodes from a Delcotron alternator, (60 amp) just one I had laying around in the garage. I made a mounting plate and had some heat sink material, mounted the whole thing under the battery where the other one was mounted. I have checked it many times and it always is running cool, no problems since I installed it about 5 years ago. The alternator on the Yamaha was only 11 Amps so plenty of room to spare on amp rateing. I would think that any diode bridge from a like source would work fine and it sure beat the $144.00 that the dealer wanted for a new one. The bike also has a seperate voltage regulator. I check diodes with my anlog meter and if the diode is good it shows about 3/4 scale. Works for me, good luck on the repairs.

Now there's a great idea. :cooler:

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Q

· #6 · Jul 25, 2009

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+1 on the possibility of digital meter not being able to test the rectifier. I'd repair the wiring and try it out before tossing it.

I've often wondered why not use a standard aftermarket 3 phase rectifier/regulator instead of the way the old wings do it with separate units. Always seemed weird to only regulate one of the 3 phases.

Q

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The New Owner

Discussion Starter · #7 · Jul 25, 2009

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Thanks a lot for all your answers! Today I went to three car electric services and none of them had an analog ohmmeter! They all measured the thing again with their digital instruments and gotsimilar readings as myself (well over 400 ohms). I waseventually told about a specialized motorcycle electronic service soI went there to discover that they also don't have an analog instrument, butonly digital :rollingeyes:. However, theservicemen measured the rectifier again, got the same readingsas beforeand said that it's ok. I emphasizedwhat the book said about the resistance but heexplicitly claimed that these readings are good. Now, maybe that's about the digitalmultimeter,as you chaps told that it will notgive the correct readings on the diodes, so maybethe diode is ok when it reads this values....but I don't know how.What I do know is that myvery next tool investment will be to buy a quality analog multimeter!

Eagledriver, I'll certainly try to make anotherrectifier by your method, at least to have it as a spare. My carbs are off of the bike awaiting the new float valves so I can't start the engine and check the charging now,so I will not throw away the old rectifier until then, though I will try to make a new one anyway. So possibly my only problem was about the third phase wire, that I resolved? As Q said it probably wouldn't be abad idea to use a merged rectifier/regulator but I don't know if it could be fitted on aGL1000, asthe voltage is regulatedby shunting the current to the ground (overloading the alternator) which I think is not the case with the recentbikes....

Again, thank you all forthe help!

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The New Owner

Discussion Starter · #8 · Jul 25, 2009

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INPUT: This evening I started with reassembling everything which I disturbed while working on the wiring (seat, switches, side bags,etc.)and when I was about to finish I've just wondered if I could test the ballast resistor as well, as there was a topic about it on the forum few days ago sothatremembered me and I had a good approach to the resistor as my carbs wereoff. Well, I had no reason to expect any surprices, all looked ok, BUT - when I disconnected one of the resistor's contacts, there was still power to the coils! So, there was a new present left by the PO. After testing with the instrument I discovered that the resistor, althoughapparently connected, was actually cut off, as neither of the two wires hadany power. So next question was how the engine stop switch gets power and the answer was directly from the "+" (black) wire, which by the way changed three more coloures untill got to the switch. And for the end, what was about the ballast bypass from the starter switch through the diode? Well, that circuit certainly was not connected with the coils at any way.After tracking down the wires (which was worsethantracking down a spider's net)I found that the output wire from the diode, which should be Bk/Br (and wassolid black in my case) was later splited into two black wires which were both going somewhere towards the headlight, where I stopped tracking them and simply cut and insulated them, which is what I'm going to do with the current ballast resistor wirestomorrow as well. God knows where does thesecome from. Then I will cut the current kill switch feeding wire and connect it to one resistor's contact, and the other contact I will connect to the kill switch. After that's done I will take the bypass output wire (that I've cut today) and connect the diode side of it with the wire that goes to the kill switch, after the resistor. And then I hope that there will benonew surprises in the wiring system. However, one of the coils is not proper but took from some other bike (made in Polland) by the PO, so that might be the reason why he wanted to exclude the resistor. But even if so, he should just short the resistor wires together and the problem is solved, while it's still possible to restore the original condition at any time.

The reason why I posted this is just to show that you can never know who worked on the bike before you took the possession. I personaly couldn'tbelieve that someone can messup the wiring so senseless as this was. So, for all the new owners of the old bikes (as myself), do yourself a favour and check the wiring system right away, that could save you a lot of troubles in future!

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2Dahorizon

· #9 · Jul 27, 2009

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The New Owner wrote:

INPUT: This evening I started with reassembling everything which I disturbed while working on the wiring (seat, switches, side bags,etc.)and when I was about to finish I've just wondered if I could test the ballast resistor as well, as there was a topic about it on the forum few days ago sothatremembered me and I had a good approach to the resistor as my carbs wereoff. Well, I had no reason to expect any surprices, all looked ok, BUT - when I disconnected one of the resistor's contacts, there was still power to the coils! So, there was a new present left by the PO. After testing with the instrument I discovered that the resistor, althoughapparently connected, was actually cut off, as neither of the two wires hadany power. So next question was how the engine stop switch gets power and the answer was directly from the "+" (black) wire, which by the way changed three more coloures untill got to the switch. And for the end, what was about the ballast bypass from the starter switch through the diode? Well, that circuit certainly was not connected with the coils at any way.After tracking down the wires (which was worsethantracking down a spider's net)I found that the output wire from the diode, which should be Bk/Br (and wassolid black in my case) was later splited into two black wires which were both going somewhere towards the headlight, where I stopped tracking them and simply cut and insulated them, which is what I'm going to do with the current ballast resistor wirestomorrow as well. God knows where does thesecome from. Then I will cut the current kill switch feeding wire and connect it to one resistor's contact, and the other contact I will connect to the kill switch. After that's done I will take the bypass output wire (that I've cut today) and connect the diode side of it with the wire that goes to the kill switch, after the resistor. And then I hope that there will benonew surprises in the wiring system. However, one of the coils is not proper but took from some other bike (made in Polland) by the PO, so that might be the reason why he wanted to exclude the resistor. But even if so, he should just short the resistor wires together and the problem is solved, while it's still possible to restore the original condition at any time.

The reason why I posted this is just to show that you can never know who worked on the bike before you took the possession. I personaly couldn'tbelieve that someone can messup the wiring so senseless as this was. So, for all the new owners of the old bikes (as myself), do yourself a favour and check the wiring system right away, that could save you a lot of troubles in future!

AMEN BROTHER:grinner:

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