I've got an 87 VT1100C that died on me on the way home from work when I stopped to idle while checking my mailbox. I tried restarting it and the batter was dead. That was pretty weird because I drove it over 40 miles to get home from work and it should have been charged.
Of course it could be the battery but mine is only a year or so old so I decided to look into other issues. After getting it home I put it on the charger and after charged I checked the voltage across the battery terminals. The shop manual said the voltage should be 15volts at 5K rpms. I don't have a tach but I rev'd the engine pretty good and the voltage never went above 12 volts so I'm not sure if the regulator is giving me enough volts.
Can somebody confirm that what the voltage should be across the battery terminals when engine running?
BTW, after charging my shadow ran fine and hasn't had any trouble starting since then but I don't want to get stuck anywhere. If there's nothing wrong with the regulator then I'll probably have the battery checked-out.
you should read between 13.5 and 14 Volts DC across your battery at approx. 3000 rpm.
With only 12 Volts you definately have a no charge condition.
First - ensure that your battery is good - it should read approx 12.6 V with the engine off, although a load test is really the only good test for a battery.
Do a quick visual for broken/chafed wiring.
Second - Unplug the 3 yellow leads from your stator and measure the AC voltage between any 2 wires, you should read about 80 to 90 Volts AC.
It you get that, the Voltage regulator/rectifier is suspect and would have to be checked out.
it should read approx 12.6 V with the engine off, although a load test is really the only good test for a battery.
I had my battery checked, and will get a better check Monday. They told me that when they did the load test, it read 9.5 volts. And this means what to me????? The battery is 23 months old, and I'm starting at the battery. What is a "good" number when a load test is done??
A load test checks the battery storing capacity, when the load is applied for a given amount of time with the correct load for that amp hour battery it should hold at least 12.5v, if it was done correctly and it showed 9.5 you get to get a new battery, the bike was kept alive by your chargeing system on that 40 mi ride.
My manual says to check continuity at the 3-wire connector that has yellow wires. I can't find a 3-wire connector with 3 yellow wires. The only 3-wire connector has 1 yellow, blue, and red wire. See the photos, below.
The first photo shows everything under the seat and the red arrow points toward the front of the bike. The 2nd photo zooms in on the only 3-wire connector. The last photo shows the other groups of connectors in case those help any.
The connector they refer to is located between where you are loking and the voltage regulator. It is about halfway up on the left side of the frome. Sorta behind and below the battery, The leads go the the stator which is on the left side of the motor. Follow the wire bundle out of the top of the stator to the connector. By the way when my stator failed one of the three leads was shorted to ground. With a ohm meter none of the three leads should have continuity to ground ( chassis frame ) but they should all measure low resistance to each other. Disconnected and with the bike running you should measure approx 70 VAC between any two wires. ( I think someone already posted that info. )
If you are still struggling, keep in mind that someone could've cut out the connector and soldered the wires directly together. On my 1990 VT1100C, the wires come out of the engine on the left hand side. Mine run straight to where the ignition switch is, and then down to the regulator. Hope this helps.
Ok, the description you gave about it being near the battery really helped. Geez, the Clymer manual really sucks in this situation. Their picture shows something under the seat near the air filter.
Anyway, now that I found the real 3 yellow wire connector, I've measured the voltage between the yellow wires and at idle, I get only 20VAC. If I rev the engine I can get to 40VAC but nowhere near 70-80 VAC. So, I guess this means I need a new stator.
I'll have to start looking online for the replacement. Hopefully Clymer's steps for removing the stator are more accurate. It does say to unbolt the slave cylinder, gearshift pedal/foot-peg assembly in order to make room. It doesn't seem like that would be needed. Is that really necessary?
I found stators on the web with a wide range in prices. BikeBandit has it for $390, servicehonda has it for $260, and gdlcycles.com has "Ricks" RK_21-104 for $150. Anybody know if there's any difference between them? Obviously the lesser price sounds good but...
Make sure when you measure your AC voltage that the connector is unplugged. You should be measuring with no load. If you do end up replacing the stator remember to also order a new cover gasket. Removing the clutch slave cylinder and shifter are both easy to do and necessary. Good luck. I got my replacement stator from Dennis Kirk, I forget what I paid for it.