Continuing Erratic Starting Behavior

[theprotege]

Continuing with my trek to figure out why my '80 GS850L has erratic starting/charging issue, I got a new battery which I'm certain held charge flawlessly. Having charged it on a tender for a night, I threw it on my bike and it started RIGHT up. After riding for a few hours, without any problems (no dimming lights or bike dying at low revs), I got back home and found that the battery was only returned to a voltage of about 11.9V. At this point, the starter button refused to turn over the engine at all. The lights would dim significantly, but the starter would do nothing. Throwing the battery back on a tender to bring it up to 12.5V and putting it back on the bike helped it start IMMEDIATELY, again. Am I looking at the dreadful stator/R/R problem here or could it be something else? As previously mentioned, all battery/chassis grounds have been thoroughly cleaned and inspected.

[sk843143]

lookup the stator papers intently...... then run the charging system troubleshooting table......... it sounds to me like the bike is not charging properly (11.9v could be just a surface charge)..... and the voltage should be around 12.4v for a battery to be considerd charged

[Steve]

Actually, a wet-cell battery should be at least 12.6 volts to be considered fully-charged, an AGM battery could be as high as 12.8 or 12.9.

For your convenience, click here for the Stator Papers Troubleshooting Chart.

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[sk843143]

yea i know 2.2v per cell 6 cells you do the math..... but it is acepted that a 12.4v (wich is more common voltage due to internal restiance and over all conditoin of the battery) is a full charge. but yes in a perfict world 12.6 is correct.

[DanTheMan]

Ground wires, ground wires, ground wires........clean them completely, use dielectric grease on the attachment points. How do I know this? been there, done that. I bought a new r/r once upon a time and I didn't need it, it was all ground wires...............

[Big T]

Well, start with the basics

1. voltage at battery at idle
2. Voltage at about 3,000 rpm
3. Stator wires okay where they connect to harness?

There's nothing dreadful about the R/R problem. Simple electrical testing will tell you what's wrong and what to replace. Just follow the Stator Papers

[chef1366]

Did you ground the R/R to the frame and battery-?

[theprotege]

chef1366,

Could you elaborate what you mean?

[Big T]

The simplest fix is to run a wire from the body of the R/R to the negative terminal of the battery.

So, check #1 and #2 that I mentioned above, then hook up the wire and check again

Also, did you follow the battery set up instructions?

[BassCliff]

Hi,

Yes, the troubleshooting chart in The Stator Papers is in order. If all of your electrical connections and grounds are clean, and you have run a ground wire from the r/r to the negative terminal of the battery, then you have a problem with the r/r, the stator, or both.

Here are some PDF files with pictures and other info:

Stator Test

Stator Replacement

Regulator/Rectifier Replacement

More On The Stator Papers

Thank you for your indulgence,

BassCliff

[theprotege]

I'll be sure to run those tests. Thank for the help, everyone!