Voltage all over the place

[skids]

I hope you can help me with my problem. I have a 78xs1100E. The voltage across the battery terminals while running is all over the place, meaning for example 13,4,9,14,8 volts very rapidly. I checked it with three different multi meters. I have used two different VRs and they both tested OK for the diodes on the bench - no difference! I bought a new battery - no difference! I cleaned the grounding contact where the VR mounts to the frame. I looked at ohms from the VR to the negative on the battery. What do you think the issue could be? Do I need to replace the VR unit with one of Geezers? PS, this is a continuance from last year…

[DiverRay]

Check the ground for the battery and engine to frame. Most bikes I've had needed these cleaned. If you have "extra" lights, I'd put a second ground wire from frame to engine. I hope you have already looked at the large connection behind the fuse box.

[skids]

Thanks Ray. I didn't think that the stator clip would affect it the way it is acting but maybe so. I did ohm the frame to neg battery post and is good. Now I am also wondering about the connection to the field coil also.

[JeffH]

Hi Skids,

Missed seeing you this year. Ray too.


FWIW, I had similar (exact) issue with my E a couple years ago.

Did all the troubleshooting you have done only to find is was the 3 Whites. At the Connector. If the wire won't bend much then 3 Whites might be the issue from heat.

Fixed those and Presto, voltage was happy per Spec.

Jeff

[bikerphil]

If you are running the Dyna coils with the solid core wires with no resistor caps and non resistor plugs, you may find your multimeter is all over the place due to RF interference. Had this problem and installed resistor plugs and the issue went away. Try an analog meter if you have one and see if the problem persists.

[Geezer]

I replied to your PM and in addition I'd say check all the connection in the harness. These are old bikes and the connectors are probably not in the best shape.

Tony

[skids]

Thanks to all. I will follow your lead.

[skids]

OK! Bikerphil wins the prize. I do have a new set of dynas and I was using the non resistance plugs. I happened to have a set of resistor plugs and that solved the meter errors. Using an analog multimeter probably would have also resolved my voltage charging display. That was actually suggested last year but I didn’t have one and I have 4 electronic multimeters - I couldn’t bring myself to buy such a dinosaur.

[bikerphil]

Glad it worked out for you Sid, it took me a while to figure out that issue on my bike. Those Dynas are awesome hot coils but throw out a lot of RFI. I have a pair of Accels that are just as hot voltage wise but do not have the same interference problem.

[cajun31]

awesome thread guys. I will be putting this one in my memory bank for future use and reference. Glad to see the problem was resolved.

[Geezer]

Analog meters are far better for bike work and are really not such a dinosaur item....

[Radioguylogs]

Every time I see the title of this thread, I can't help visualizing this:

[skids]

Hi Skids,

Missed seeing you this year. Ray too.


FWIW, I had similar (exact) issue with my E a couple years ago.

Did all the troubleshooting you have done only to find is was the 3 Whites. At the Connector. If the wire won't bend much then 3 Whites might be the issue from heat.

Fixed those and Presto, voltage was happy per Spec.

Jeff

Jeff, I have been missing out on a lot of things! I had a radical prostatectomy on June 11, followed by a major infection of e-coli which complicated healing of the operation in a big way. Good news is the cancer was contained to the prostate and my psa is below detectable limits. Yeah! So, I am on the mend. I lost 25 lbs in two months but I gained back 4. This is more than you asked to know but I am happier now. The xs1100 runs like a dream. I drug it out of storage after the new battery, plugs, and a little gas, and then took her out for new gas. Loads of fun!