(another) melted connector at the altenator wires

[markmartin]

Does anyone know what the voltage should read at the wires coming out of the alternator?

  Thanks to a recent post http://www.fjowners.com/index.php?topic=13052.0, I found that my connector was melted and very corroded.  This may be the source of a voltage problem I'm trying to figure out.  Movenon / George, thanks for posting that picture!  I replaced the connectors last night and am going  to test it out tonight. 

[markmartin]

After further searching, I may have found my answer at this site. http://www.electronicamotos.com.ar/technical-resources/library/known-issues/street_65700.html 

The voltage is listed for the sensing wire (brown) as being close to or the same as the battery voltage.  I'll check that.  I'm still curious if the generator is putting out the required voltage?  Or does it matter ?
 
anyway, here's what the link had to say...

Common Technical Issues: YAMAHA FJ1200
BRAND: YAMAHA
MODEL: FJ1200
YEARS: 86-93
CATEGORY: MOTORCYCLE

TECHNICAL ISSUE DETAILS
This Yamaha model uses a Nippon-Denso car-type alternator that is mounted behind the cylinder block. Inside this alternator there is a field rotor with copper slip rings on which carbon brushes run. Around the rotor you will find the stator and in the front of the housing are the built in rectifier bridge and the electronic voltage regulator. Common faults: FAULT 1: OVERCHARGING THE BATTERY. This is usually caused by (1) a bad internal voltage regulator or (2) a bad electrical connection somewhere on the bike in the lead that provides battery voltage feedback to the internal voltage regulator (the voltage sensing wire) The replacement voltage regulator is our part# ESR025. This unit replaces the OEM unit even though it looks different. To find the bad connection to the voltage sensing wire you need to look at the leads coming from the alternator. There is one large diameter lead, usually RED, that is the output from the alternator to the battery. The thinner lead is the sensing wire for the regulator. Use a multimeter to measure the voltage on this lead to ground. It should be close to the battery voltage with the bike running (around 14Vdc). If you see a substantial difference (say: battery voltage 17Vdc, sensing lead 14Vdc)you should look for a bad connection somewhere between the battery and this sensing lead. Inspect all connections, the ignition switch, use spray contact cleaner on everything. Spend some time and you will probably find a bad connection somewhere. Fixing this connection should fix your overcharging issue. FAULT 2: NO OR LOW BATTERY CHARGING. This can be caused by a bad internal voltage regulator inside the alternator, or by a bad rectifier module. A bad voltage regulator sometimes is caused by a shorted out field rotor that is drawing too much current from the voltage regulator. Inspect the rotor resistance between the slip rings which should be 3.3-4.0 Ohms. Another cause could be bad connections between the alternator output and the battery terminals. Check all connections and see if this fixes the issue.

[markmartin]

Great news on my voltage problem.  The infamous red connector seems to have been the source of my problem.  I cut out the old connector and installed new connections and everything is better than back to normal.  The voltage drain I was getting when using my 55W running lights has disappeared, and that was what I was the problem I was trying to solve. The reading I get now on the brown sensor wire is just .01 V or .02 V less that the reading I get across the battery terminals.

Question:: Is it possible that this would also allow for a better spark at the plugs?  I'm not sure if it works this way.  ?  I did change the plugs at the same time I was doing this so maybe that's it, but the bike is starting more easily.  I require little choke now, as where before I needed full choke with a cold motor. The plugs I replaced were had 20,000 miles or so on them and seemed ok color.

[movenon]

I don't have a direct answer to your question but having as much voltage as you can get to the coils is good.  I recently did the coil relay mod and it made a difference.  I use to think that it wasn't really needed but now "I see the light" . 

I don't know if any of this really helps but it is what I have done.  I converted all my lights (except the low fuel bulb in the cluster and turn signal bulbs) to LED's to help reduce the total running load (amp draw).  I might do the turn signals someday but they are only on for a short time.  The headlight/taillight and running lights when I have them on probably take the most current.  Also converted the regulator to an adjustable unit, externally mounted helping reduce heat in the alternator and keeping the new regulator cool.  I keep harping on this but a small digital volt meter mounted on the FJ is a nice thing to have. They are dirt cheap on e bay.  A lot of batteries probably have been cooked by owners not knowing what the running charging voltage was.

Again this is just me.  When I change plugs I mark where the back side of the electrode is on the plug insulator with a Sharpie and install them to about 10lbs then check where the back side is,  and try to position the plug as best I can so the open side is facing toward or perpendicular the intake valves. My thought is to not shroud the spark from the intakes.  A very minor thing and I have no evidence that it helps other than my bike starts great or certainly a lot better than before I started making changes.  In the old days we use to index the plugs and had different thickness of copper washers to help accomplish this.  On the FJ I just Tq to about 10lbs then start checking.  Some plugs might be slightly under spec and some over but not to far...... Not worth stripping a plug thread out..
George