'78 750 regulator/rectifier ???

[nichols750]

I was trying to work through the stator papers last night everything was going ok until i came to phase C. I know my R/R is 2 separate units, how will that effect the tests in part c? When i did steps one and 3 i got no reading at all, and on steps 2 and four the reading was .586. what does this mean?? when i tested the part that has the heat sink built into it. i think that is the regulator? the other part under the battery pan has only one yllow wire and one ground wire. i wasn't sure how to test it.
i need your help,

[jm_foote]

Please correct me if i am wrong.

The part with the heat sink is the rectifier. It has the diodes in it.

Part "C" is just testing if the diodes work. The idea is to make sure that the diodes only pass current one way (diodes only let electrons pass in one direction, allowing us to "rectify" alternating current to direct current). The instructions are a little confusing because not all diode test readings are the same, as it is not really determining "volts" (voltage is potential difference, and the r/r should be disconnected from the bike).

As for your questions:

The separate regulator should not effect the part "c" test, because you are testing the diodes and not the voltage coming from the stator.

Your readings, it seems to me, indicate that all your diodes in the rectifier are working correctly (possibly good news!).

Might I suggest, however, purchasing an aftermarket r/r from ElectroSport as they are "better" and cheaper than replacing the individual parts. They supposedly protect your stator as well. Also, make sure all your connections are good. If they look corroded or melted (as mine did), make sure to replace those (solder and dielectric grease are your two best friends here).

I'm curious; what did you get for your AC voltage?

[nichols750]

AC volts from the stator, right? I was getting about 63 on all 3.

can i just use a R/R from a newer bike if all the leads are the same?

thanks

[nichols750]

AAAAAAAARGH

i went to work seom more this problem last night and now it seems that my battery is fried. the last time i started my bike was to test the stator and now i get no power from my battery and my charger won't charge it. Can testing the stator kill a battery?? my thought is that if the battery got a current from the stator without going through the rectifier it kills the battery. Is that right, what do I do now??

[jm_foote]

What were your symptoms to start out with?

[nichols750]

kind of a long story but, here it goes

i have had this bike for about two months, but a new battery in about a month ago. no problems since . . . until

i was at work, i work at a chevy dealership, i took my bike into the wash bay and gave it a bath, and drove it out front and parked, about three hours before i went home. then i left work went aobut three blocks and it died, when i coasted to a stop it would barely turn over. so i took it back to work and put a battery chager on it over night, then the next morning it started fine, i then took it home and check the battery, it was quite low, so i charged it again, drove around the block and check again, and it was lower than when i left so, I decided to go through the stator papers and test every thing. i think every thing is ok, except maybe the rectifier? (see first post)
now it's been a couple of days since i tested everything, i went home last night to try some re-testing, and it wouldn't even turn on the dash lights, the battery is totally dead and won't take a charge.
i'm at a complete loss, i don't want to but in a new battery if it is going to fry another one, but i want to be riding.

PLEASE HELP

[jm_foote]

How much voltage are you getting at the battery when the bike is running?

Almost sounds like there is a short somewhere. Other than that, I can't think of anything.

When the ignition key is off, there should be ZERO power draw off the battery.

Go over EVERY connection. Make sure they are clean. Check the wires for shorts. Get a soldering iron and some dielectric grease.

Good luck!

[nichols750]

I think i was getting 12.?-13.? when the bike was running, but i'm not sure it was a lot of tests ago. i dug out the soldering iron last night, need some grease, can i get that at any auto parts place? what should i use to cover the soldered connections? elec tape?

[jm_foote]

Heat shrink works better.

I personally soldered on all new connectors. I bought some new bullet connectors and a modern ATC fuse. The bullet connectors came with polymer shielding that slipped over (making soldering difficult). Then I smeared dielectric grease all over everything after cleaning the connections with a wire brush.

you can get dielectric grease at an auto store.

If your getting 13 volts at any time, then you have enough power from your system to run the bike without battery power (DO NOT DO), so your bike should not have randomly stopped (unless you have a poor connection).

[normGS750]

similar situation

1977 GS750 titled as a 1978

This bike has a two separate OEM unit’s for the Voltage regulator and Rectifier.
A 2 wire Voltage regulator that is attached to the bottom of the battery box and a Rectifier attached on the left side of the battery box.
On the regulator it has one yellow wire that connects to the twined connector yellow stator wire and one black/white wire to ground on the voltage regulator housing.

Does anyone have ideas on how to test the 2 wire voltage regulator while it is out of the bike. ???

Yes I have read the Stator Papers a couple of times, even made up a note book.

voltage regulator is just like this one for sale (see picture)

http://cgi.ebay.com/ebaymotors/1978-SUZUKI-GS750-CDI_W0QQitemZ110141232811QQcmdZViewItem

1977 GS750 OEM 2 wire voltage regulator, Suzuki part # 32500-45011,
Nippon Denso part # 137600-0012

Just finished cutting out all the bullet connectors and replaced them with insulated blade connectors. The process I used was the strip the wire, twist and tin then crimp followed with heat shrink as a strain relief . Then use dielectric silicon grease to plug them back together.
I am in process of tying/splicing into both the voltage and rectifier grounds back to reference the Neg. battery post. At the suggestion of another member.

Thanks, norm