XS1100 charging problem

[Graham]

So is this an alternator or a PM generator like a GS? I'm confused?

Alternator. you can see it in the pictures. Yamaha-ha-ha-ha trained by Lucas in the electric arts.

[old_chopper]

I checked last night and the field coil is not getting 12V. I'll look into this tonight to see why. Currently there is just 1 main fuse and it's not bad. I'm certain the regulator is hooked up to the battery on the positive side. Thanks for all the replies so far! I'll update when I have more info.

[Matchless]

If the field coil is not getting 12V the regulator is probably the culprit or any connections to or on it. If you have brushes on the rotor, check those, if they are OK you can briefly power the rotor directly from the battery via a fuse and see if it starts charging. Some field regulated alternators receive the excitation voltage via the charge lamp on the dash if there is one and will not work if the bulb is blown.
Do the feeler gauge test with the battery directly connected via a fuse to the rotor without the motor running.

Hope this helps.

[old_chopper]

If the field coil is not getting 12V the regulator is probably the culprit or any connections to or on it. If you have brushes on the rotor, check those, if they are OK you can briefly power the rotor directly from the battery via a fuse and see if it starts charging. Some field regulated alternators receive the excitation voltage via the charge lamp on the dash if there is one and will not work if the bulb is blown.
Do the feeler gauge test with the battery directly connected via a fuse to the rotor without the motor running.

Hope this helps.

I just set down to ask this very question, can I temporarily supply the 12v diretly from the battery to see if I get my AC output. Thanks way in advance for the answer.
There are no bulbs on the bike, I have stripped nearly everything to start from scratch. It set outside for 17 years and most parts were shot. Amazingly the motor sounds pretty solid, just a slight smoke that might clear up with some hard riding.

[Matchless]

Usually the rotor windings can handle the full 12V, that then means that getting full +12V will enable the alternator to give out maximum voltage. The regulator will usually vary that voltage down to keep the voltage over the battery steady at say 13.8V. You may find with a full 12V on the rotor that the alternater could put out 16 or more volts.
I assume that the ground for the one side of the rotor winding is most likely wired in permanently.

Disconnect the regulating positive wire to the rotor and connect a piece of wire via a 10 A fuse that would reach the pos terminal of the battery. Touch it briefly with the bike not running and check if a feeler gauge close to it is magnetically attracted. If so then the rotor may be in order. If not check out the rotor, it should also have a very low resistance of a few ohms (manual will give it).

If the rotor checks out OK statically, then put a voltmeter across your battery, make sure lights are disconnected, as you do not want to blow them. Start the bike, watch the voltmeter and briefly touch the wire from the rotor to the battery positive terminal and push up the RPM's a bit. Voltage should jump to more than 14 V maybe even 16V or higher. This is applicable assuming the rectifiers are still good.

That then proves your regulator is shot or not properly terminated. You most probably know that an internal regulator for some car alternators can be made to work. I do not have the exact details, but there are some ways to be found on Google. The BMW riders have lots of threads on that.

PS As Graham said earlier, energize the rotor and measure the AC output with the stator unplugged. If your AC is present the stator is good

Good luck

[old_chopper]

Put the stator and field coil back on, hooked the ground to the frame and made a jumper to go from bat + to the field coil. Feeler gage test was good. Fired the bike up and had 15+AC output across all 3 leads from the stator at idle, increasing quickly with RPM. Stator is definitely good. Hooked regulator back up, ensured 12vdc to it, grounded directly to the battery, zero output. It's not sending 12vdc to the field nor connecting to ground to field. I'm saying it's shot. What are my options to replace it?

[Graham]

Put the stator and field coil back on, hooked the ground to the frame and made a jumper to go from bat + to the field coil. Feeler gage test was good. Fired the bike up and had 15+AC output across all 3 leads from the stator at idle, increasing quickly with RPM. Stator is definitely good. Hooked regulator back up, ensured 12vdc to it, grounded directly to the battery, zero output. It's not sending 12vdc to the field nor connecting to ground to field. I'm saying it's shot. What are my options to replace it?

All you can do is replace it. BTW doesn't always get 12v, the reg controls field voltage to control stator output.

[Matchless]

Put the stator and field coil back on, hooked the ground to the frame and made a jumper to go from bat + to the field coil. Feeler gage test was good. Fired the bike up and had 15+AC output across all 3 leads from the stator at idle, increasing quickly with RPM. Stator is definitely good. Hooked regulator back up, ensured 12vdc to it, grounded directly to the battery, zero output. It's not sending 12vdc to the field nor connecting to ground to field. I'm saying it's shot. What are my options to replace it?

This may help you, all the Honda CB's used field regulation. Here is a Shendengen SH236-12 that uses field regulation.
Here is one for $25 http://cgi.ebay.com/1980-Honda-cb900...item3a5f792450


Edit: The above diagram is for explanation purposes only see post #29

[old_chopper]

I found the problem. I missed on the schematic that I needed a switched 12vdc to the regulator. Hooked it up and I have 14+vdc output. All is good now. Well not nearly all, still have no brakes, tank, seat, fender, etc...but it's charging and that's one item I can mark off my list.

[Matchless]

I found the problem. I missed on the schematic that I needed a switched 12vdc to the regulator. Hooked it up and I have 14+vdc output. All is good now. Well not nearly all, still have no brakes, tank, seat, fender, etc...but it's charging and that's one item I can mark off my list.

Lucky! A nice cheap fix, only your time!

[old_chopper]

Lucky! A nice cheap fix, only your time!

Actually I picked up a used regulator thinking mine was bad. Turned out good though cause I found a nice 160 mph speed-meter while I was there and got a good deal on both parts. I don't mind having a spare regulator on hand.

[Matchless]

Actually I picked up a used regulator thinking mine was bad. Turned out good though cause I found a nice 160 mph speed-meter while I was there and got a good deal on both parts. I don't mind having a spare regulator on hand.

Having a spare of anything is good and as per Murphys law that makes the chance of your regulator failing very remote! This above the peace of mind that you have a spare one.

Keep well.

[Graham]

This may help you, all the Honda CB's used field regulation. Here is a Shendengen SH236-12 that uses field regulation.
Here is one for $25 http://cgi.ebay.com/1980-Honda-cb900...item3a5f792450

Your posted wiring diagram is wrong. No hot to field coil side of regulator, just a ground.

[Matchless]

Your posted wiring diagram is wrong. No hot to field coil side of regulator, just a ground.

OK you are right that diagram is not exactly for the Honda R/R in the photo. That is just a common diagram showing field regulation in its simplest way and was what I had lying around here.
I should have mentioned it, but we should always use the diagrams that come with the service manual.

The Honda R/R has two thin extra wires in the larger plug together with the 3 yellows. Those go to the rotor brushes.

The smaller plug has the heavy positive and ground and the sensing wire that connect to a switched positive.

Thanks for pointing it out.

[Graham]

OK you are right that diagram is not exactly for the Honda R/R in the photo. That is just a common diagram showing field regulation in its simplest way and was what I had lying around here.
I should have mentioned it, but we should always use the diagrams that come with the service manual.

The Honda R/R has two thin extra wires in the larger plug together with the 3 yellows. Those go to the rotor brushes.

The smaller plug has the heavy positive and ground and the sensing wire that connect to a switched positive.

Thanks for pointing it out.

Here's a hot for your wiring diagram.

Hope I didn't break any rules.