77 650 alternator

I'm not getting any output from my alternator. I checked by disconnecting the three wires and putting the leads from a meter on each one. I checked stator resistance and that seemed fine so that would point to the rotor as the problem right? Did the way I checked the voltage get an accurate reading? Thanks for any help.

The 77 rotor depends on the field coil to work. To check the field coil, disconnect the green wire from the voltage regulator and measure the resistance between the green wire and ground, you should see 2.7 - 3.4 ohms.

Also, as always, check for corroded connections, broken wires etc., could simply be the field coil doesn´t get any/enough power.

If all this checks out I´d suspect the regulator.

I'm getting 4 ohms between the green wire and ground. I will double check the connections again, Ive tried swapping out both the reg and rect. didnt help.

ZippoMan, as you have a Electro Magnetic Charging system, you have to "Full Field" the Field coil to test Volts AC out of the stator, you need to disconnect the stator wires and start the bike then just hook 12 volts to the field coil wire to "full field" the coil and check 1 to 2, 1 to 3 and 2 to 3 on the Volts AC setting.
generic spec's are 15- 100 vac,
or a better test would be the loaded stator output test were you just check 1 to 2, 1 to 3 and 2 to 3 while they are still connected and the reg/rectifier hooked up with the bike running
generic spec's are 9- 20 vac

don't forget to check for insulation breakdown by checking any of the stator leads to ground any continuity means your stator has a short to ground in it and must be replaced.

you can check the rec/regulator on some models but as I don't know about the one on your bike I will omit testing directions till I have a chance to look at the schematic

when I left 1 yellow wire from the stator connected I got 45 volts @ 3500 rpm between the other 2, the same for the other wires when tested. Got a good spark between 2 of them they touched.:blink: What voltage should I be seeing from the rect. white wire going to the battery?

thanks

looks like from the schematic in the filebase that you should be getting Volts DC from the white wire, generic spec's as I don't have specific data for your bike is 11 - 15 volts DC

Hi zippoman.

Check the brushes and slip ring surfaces for deposits or oil residue too. It's a weak point on most vehicle alternators. BTW I'm assuming these bikes have alternators with brushes - not because I've been into my KZs alternator yet...

The brushes and slip rings are what puts current through the rotor. If you don't have a consistent electrical connection to the rotor, you'll get zilch out of any alternator.

I work in a 500 megawatt power plant BTW, and we change the brushes with the machine on line (1100 amps at 200 volts). A delicate operation, to say the least .

Post edited by: Idaho_Spud, at: 2005/10/22 14:01

thanks for the replies, charging the battery so I cant check it till sunday. Does it make a difference if I check the output on the wire connected or not to the battery. I do seem to be getting good voltage from the alternator.
thanks again

Well done and congrats on getting your alternator working again. The best way to ensure it's working is to start it up, disconnect the positive terminal on the battery and connect an ammeter between the positive wire and the positive post. You should get a couple of amps positive into the battery.

no slip rings or brushes on the 77 650 alternators. It uses a field reversing rotor. THe electromagnet is fixed to the cover as is the stator.

Thanks for that, loudhvx. Guess I ought to get off my butt and get a repair manual

That's why it's such a good design. No moving parts touch each other. But it's expensive and Kaw kind of blew it by using an antiquated regulator/rectifier design.