Charge dropped, bike died, the search starts

80 750E1

Usually I see about 14VDC on the handlebar voltmeter, but today after about an hour ride I noticed that was dropping. Got down to 8 VDC or so. Before I could get home it started running crappy and finally died quite suddenly...no lights, no nothing, dead battery, no kickstart. Snot.

Maybe or maybe not related, the bike seemed really hot. Generator cover was hot enough to sizzle water from my drink.

I'm not an electrician. Been reading the forum quite a bit and it seems to me a likely approach is to...

check fuses
check wires overall
check wires from alternator specifically
look in alternator for bad wires under cover
replace reg/rec

If that doesn't work, replace stator, or rethink electronics completely.

You guys see anything else I should be doing here? Are these symptoms "classic" of anything?

Thanks

Post edited by: bluegill, at: 2006/06/24 22:53

Pull the battery and check the fluids too.

Check the connection to the reg/rec.

Charge the battery back up and run the Electrical System flowchart tests found in the filebase.

What type bike is this? Since your bike has a voltmeter, I suspect it is either not a 70s Kaw or is from another bike manufacturer. Perhaps the KZ750 has a voltmeter? I hate guessing at this stuff so please make your model/year clear when posing a tech question as I am reluctant to make guesses based on assumptions that will only make me look like an idiot.


IF IT IS THE KZ750, then you should have about 14VDC when operating at speed. If the regulator/rectifier malfunctions, the voltage you would see would be more likely to be higher... bulbs will start blowing and other symptoms of that type. If your stator shorts, then it may not produce full power and I would expect a voltage drop as it produces the AC that is converted to DC.

All this presumes the battery is OK. First, get the battery load tested but you could also buy a cheap hydrometer at the autopart store... directions for interpreting the colored balls are on the packaging. You suck in some fluid from each cell and colored balls will float or not float and these will tell you if you have a bad cell. If the battery shorted internally, this could produce a decreasing DC voltage.

If the battery checks OK, the steps provided in the already mentioned troubleshooting guide will help you pinpoint the problem but you could also use your Kaw service manual or Clymer manual for testing the three wires coming out of your stator. These are pretty simple tests which would help pin down a possible short. The three wires are extensions of three separate electromagnetic windings, all of which are coating in plastic stuff to keep them from touching each other... I have seen only a few of the windings short; more often it is the wires where they attach by crimp connectors inside the stator where the problem occurs or in the insulation near the stator cover which cracks and allows the wire to become exposed.

Thanks WiredGeorge.

It's the 80 750 E1, as stated in the first line of my post. It does have the voltmeter.

Battery's 2 months old, but I'll check the cells.

Your point about the reg/rec and voltage increase is news I hadn't found in the archives. I'll start with the stator, and have already downloaded the troubleshooting guide.

Do not know if these alternators use a slip ring or commutator but in either case, a shorted rectifier phase(rectifier will be hot too), shorted cells in the battery(new battery dropped by stock monkey prior to being sold), excessive load on system(4 x 55W HID lamps added for example), and worn out brushes will present the symptoms described. Might be others but it's late and I'm tired.

Sorry... read right through the first line and looked at your signature which contains a bunch of bikes... Most of the reg/rec failures I have ever seen involve higher than 14 VDC voltages and that means burned light bulbs and hot wires generally. Your symptoms seem to point to the stator or generator or whatever it is called.

sounds like you lost a leg of the 3 phase ac dynamo. time to check the stator for insulation breakdown.

Following up...it was the old fusebox and some worn out wiring. Replaced the fusebox with the new type block, changed some other suspect connections, and it's charging again. Lucky for me.