Stater Papers Question

[77 gs550]

I own a 1977 gs550, almost 30k miles. At first, I was boiling batteries. Now it appears I am not charging.
I went through the Stator Papers last night and I find:
The Stator is putting out about 70 volts through all three legs. But I couldn't get a reading with the diode test they talk about. No reading at all for that test. (Or I was doing it wrong.) I think the R/R is fried, because none of the tests in part c of the stator papers check out on my bike. I took it off the bike, and checking it in my hand, None of the tests were within specs.

My question is: if my stator is putting out 70 volts on each of the three leads, Would it stand to reason that the R/R is to blame.
Battery voltage when running doesn't raise above 11.5 or so volts.
Battery is about two weeks old. All connnections are like new. (Bike stored inside for it's whole life.) I will do the ground wire upgrade from the R/R ground wire to the Neg battery terminal. (also My R/R appears to have one mounting hole through the direct center of it, with the Black/White stripe wire grounded to the mounting screw through the middle of the unit.
Just trying not to throw money away...I will buy whatever is necessary however.
Can the Stator be faulty and still put of clean even voltage within specs?

Thanks.

[basic]

your logic seems correct, the stator is putting out 70ish volts on all 3 legs, and there's no connection to a ground, so I would say it is okay and the R/R is to blame. Do yourself a favor and get one of the honda ones from duanage here on the forums, they work wonderfully.

[77 gs550]

Honda R/R

What makes the Honda R/R's better than the Electrosport ones, or a new OEM one for that matter?

[Steve]

What makes the Honda R/R's better than the Electrosport ones, or a new OEM one for that matter?

The Honda units use heavier gauge wires, better heat sinks and some of them have a 'sense' wire that helps control the output.

Just another question ... do you have separate rectifier and regulator or are they combined like the later units? I know that some of the bikes before '78 or '79 had separate units and others had them combined, I just don't know which way yours was.

If they are separate, you will do the diode test to the rectifier. If they are combined, you will still only be testing the rectifier, but it is combined with the regulator.

If you have separate units, it is still possible to upgrade to a Honda unit. You might have to rig a connector or two, but it is a simple and reliable upgrade.

.

[basic]

well, there has been some discussion on the electrosport R/R. The primary difference it seems is price. Honda R/R for $40, electrosport one for $100.

As for the stock unit, it's problem lies in the way that it rectifies and regulates the stator voltages. It seems that the way it is made it normally rectifies/regulates only 2 of the 3 legs of the stator. When switching on the headlight (which we here in the states have on nearly all the time), the 3rd leg is added and this load is too much for the R/R, ends up breaking something and the magic smoke gets out. The honda unit however, always regulates all 3 legs and is much a much beefier unit. It's a bit larger, but that's because it's doing the work it's supposed to. Some also say that because of the sense wire it does a better job keeping the voltage regulated.

[77 gs550]

separate?

I think mine has a separate Regulator and Rectifier. Again it's the earliest version a 1977. There is a small silver box about 3 inches by 3 inches that is mounted on the battery side, under the left side cover. It has one lead from the Black R/r/ and one lead to ground on the frame. The other Rectifier/Regulator is black, and has the five leads (with proper coloring) and is mounted under the right side cover.
Could this be why I can not correctly test the Diodes in part b of the stator papers? Or why there are no readings at all when I try?

Also, I do have a headlight shutoff switch. Does this throw a curve into the equation?

[Steve]

The headlight switch should not enter into the equation at all.

With separate units, test the rectifier as specified in the Stator Papers. The rectifier will be the one that has the five wires. Three of them connect to the stator, one is a ground, the other will be a DC wire that then goes to the regulator. If you find you have a bad rectifier or regulator, you can replace them both with a single Honda unit from duaneage.

.