Issues with the charging system

[BigOates]

I used the "Charging System/Tachometer Tips and Troubleshooting Guide" in an attempt to address the bike not charging while riding. I've been working on getting the bike back on the road. It's an '81 special with an '80 special motor and ignition system.

I took it for a test ride the other day and could not get it crank when I stopped for gas. Took it home and hooked it up to my battery tender. A repeat test ride last 15 minutes had the battery voltage at 12.9v with the ignition off, 12.3v right before I started it. It maintained 12.3v for a bit and was at 11.7v by the time I returned. I purchased a new battery and cleaned all the connections with the same issues resulting. I'm thinking it's the regulator/rectifier, but wanted to run it past someone elsebefore I spent the $$$ on one.

Here's the measurements I recorded using the guide in the repairs section.


White wires from the stator measured between 0.4 and 0.6 ohms. (Supposed to be 0.4 ohms (+/- 10%)
The resistance between the brown and green wires was 3.7 ohms (Supposed to be 3.5 +/- 10%)
With the ignition on, the brown wire grounded to the frame was 11.08v (12v)
With ignition on, green wire grounded to frame was 1.24v (<1.8v)
With the bike running at idle, green wire grounded to frame was 0.78v (Supposed to be 9-11v).

[D0wn5h1ft]

Measure the resistance between each white wire of the stator and your frame/the aluminum housing the stator sits in. I guarantee that you'll read a few ohms.

The resistance between each of the three white wires and ground should be INFINITY. This is because the stator wires are supposed to be coated in that brown enamel/varnish and never come into contact with the frame of the bikes (otherwise all of your electricity goes straight to ground instead of into your voltage regulator and then into your battery).

Source: I had this EXACT same issue until I replaced my stator. Also, I'm an electrical engineer...

[trbig]

Also, I'm an electrical engineer...

Ahhh... So you know how to control that electrical magic smoke stuff... but can't tie your shoes? lol.

[BigOates]

Just went out and checked it and can say that you were right, all three had continuity with ground and were reading around 3 or 4 ohms. Glad I didn't just throw money at the problem!

Now to go dig through my shed... I'm pretty sure I have another stator in the spare parts. At least I think I do, haha!

Measure the resistance between each white wire of the stator and your frame/the aluminum housing the stator sits in. I guarantee that you'll read a few ohms.

The resistance between each of the three white wires and ground should be INFINITY. This is because the stator wires are supposed to be coated in that brown enamel/varnish and never come into contact with the frame of the bikes (otherwise all of your electricity goes straight to ground instead of into your voltage regulator and then into your battery).

Source: I had this EXACT same issue until I replaced my stator. Also, I'm an electrical engineer...

[D0wn5h1ft]

Just went out and checked it and can say that you were right, all three had continuity with ground and were reading around 3 or 4 ohms. Glad I didn't just throw money at the problem!

Now to go dig through my shed... I'm pretty sure I have another stator in the spare parts. At least I think I do, haha!

If you don't, I have a extra stator floating around here somewhere I'll sell you dirt cheap plus the cost of shipping. Or they sell them on ebay for ~$30 after shipping.

http://www.ebay.com/itm/YAMAHA-1980-...959ecd&vxp=mtr

Ahhh... So you know how to control that electrical magic smoke stuff... but can't tie your shoes? lol.

Pretty much, 4 years of college education but I can't get my motorcycle to start

[BigOates]

Thanks for the help Gabe. It's fixed now. I found the extra stator and had to solder on the wiring and connectors from the old one (Apparently the guy I got my parts bike from cut the wires half way down instead of unplugging it...). Took it for a test ride and it's showing 14.5v at around 2-3k now. Oddly enough I think it fixed an issue with the bike missing intermittently at idle and under load. I'd been trying to chase down for over a month!