stator

[Steve G.]

Steve, I found a piece of alloy to mount your new regulator. 6”x3”x1/4” thick. Will that do, if so I will bring it to coffee next Wednesday.

  Actually, it’s as close to perfect as I can imagine!! And 1/4” thick, truly perfect!!! Thank you!!!

[Steve G.]

As per Johns request, here's the list I've got:

  Charlie's Place

 Grant Tiller

 Parts n More

[Wheels]

As Ross mentioned on another thread Mrs Wheels is having charging problems on her 1981 CB650 Four.   At coffee this week it was mentioned to replace the  regulator/rectifier with it  being the easiest and cheapest possible fix over the stator and rotor.
At the same time i am getting a reading of 5 ohms on the rotor itself which I believe is too high of a reading.  Bike runs fine and only discharges the battery after about an hour of riding with the headlights on.  My understanding is even the bike when new had low readings from the start as the factory did not make a very good unit and could barely maintain its battery from the get go.  I see where we replaced the rotor two years ago here but now thinking that replacement rotor might not have been good from the beginning and it only took a long ride for us to notice the battery becoming dead.

Battery is good so now I believe if correct that it must be one of three things, regulator/rectifier,  stator and rotor.  Plus also checking and cleaning the wiring of the unit.

Any further input is welcome as this is a great bike when running properly.

[Wheels]

Thanks for the list Steve and we have been on all four sites and looks like if necessary we can get all three required items and then when they fail to work just leave the garage and go out and have a fit! 

[hardrockminer]

I don't know much about the Honda charging systems but on the Kawasakis the rotor is on the crankshaft.  The stator sits inside the left engine cover and it's wires go into the rectifier.  If Honda's system is the same you would not be measuring the rotor resistance. 

The old bikes generated just enough power to run the lights and that's about it.  Kawasakis run around 45 to 55 volts per phase but at fairly low amps.  I think they are tested at 4,000 rpm but maybe my memory is faulty. I think once converted and supplied to the motorcycle electrics they only provide around 250 watts.  So if you're trying to run anything extra like heated gloves it's probably too much for the charging system.

My thought would be to measure voltage from phase to phase on the stator.  If it meets the spec then you are probably getting all you can get. 

[Hawkeye]

A common issue on older Hondas is the connector where the alternator wiring joins the main wiring harness. The terminals in Honda connectors were made of un-plated copper or brass. Over the years, the terminals become oxidized, which increases the resistance of the connections. This causes the terminals to heat up, further adding to the oxidation, further increasing the resistance ... Eventually, the plastic bodies of the connectors start to melt.

On nearly every bike I've put on the road, I've replaced the original connector with a screw-terminal strip, with a shot of corrosion preventive sealant in each barrel. Still easy to disconnect when removing the engine, but very good at holding off the oxidation.

[Wheels]

Thank you for the input everyone.   Will update once cured and on the road.

[Bucko]

A bit late to the table on this... 

Your rotor resistance seems a bit high, but before doing anything drastic, try measuring with another meter.  Unless you have a really good meter, the meter's 'error spec' could be as much as a few ohms so when measuring low ohm devices (like the rotors in these bikes), the resulting measurement may be way off.  And, be sure to zero out the ohmmeter before making the measurement, if you can, or if you can't, make a note of the resistance measurement of just the probes and subtract that from your rotor measurement.

The common problem with these rotors is that with high speed spinning, the wires chafe and eventually short out (resistance would measure less than the spec) which reduces the rotor's magnetic field, which in turn reduces the stators AC output.  To compensate, the R/R passes more current into the rotor to try to increase the Rotor's magnetic field.  Eventually the R/R overloads from passing too much current to the shorted rotor and it burns out.  The R/R can be tested but you need two batteries or a variable power-supply (with at least several volts more than 12v available). 

Of course, the rotor can also fail with a broken wire, i.e. 'open circuit', but that easy to diagnose. 

[Wheels]

Thanks Dave.   If anything I will take this as a learning curve
Electricity is not my skill and I am surprised mom and dad did not name me Lucas

[Tripleted]

FYI…Jameson Mc Murray has a nice original 77 XL 350 with original muffler in nice shape and original signal etc for $1500 if anyone is interested.