Wildguzzi.com
General Category => General Discussion => Topic started by: wirespokes on September 25, 2018, 07:35:55 PM
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My 87 LeMans Volt meter sucks. Big time! It's practically worthless. The needle has at least a three volt swing - back and forth.
The speedo and tach work fine, though the needles jiggle at the low end, but smooth out a little higher.
Anyway, I've checked the connections to the volt meter and they're bright and shiny, so it aint that.
My question is if these volt meters are all like this - in which case I won't bother trying to fix it. I've tried fixing the Moto Meter volt meters on airheads and most times if it isn't bad connections, they're junk. I replace them with VDO upgrades, but I don't know if I could do that with the Veglia (install a VDO movement into the Veglia housing).
Right now the gauge looks good, so don't want to uglify by trashing the thing and leaving an empty hole. Is there any hope for this thing?
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In my experience they work well when new but needle movement is typical after a few decades. However, I replaced one on a '79 LeMans in around 1990 and that one still seems fine.
Needle jiggle on the speedo and tach is usually cable related.
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In my experience the Veglia voltmeter on '80s Guzzis is very inaccurate. I'm not sure if that's due to where it's tapped into the harness or the gauge itself.
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I'm not sure if that's due to where it's tapped into the harness or the gauge itself.
Probably a little of each. On my 87 SPII, the gauge is inacurate as to numbers. I consider it binary. The needle either goes up when it is charging or it does not when it is not charging. Pointing to some number is irrelevant. That is until I hit the front brake switch (not the foot). When I grasp the front brake, the needle bottoms out until I release the brake lever. I suspect that is an indicator of other shoddy connections in the front of the harness and an irregular or unreliable path to ground.
Patrick Hayes
Fremont CA
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On my Lemans 3, it frequently shows a discharge until I tap on it. Then it seems to work for awhile. The idiot light works fine.
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I've had good luck by cleaning and De Oxiting every connector hooked into the volt meter circuit. The fuse block seems to be the first to corrode for whatever reason, and is generally why the volt meter starts to slowly creep lower. I changed to a digital regulator on the AeroLario, and that helped, too.
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All of the above, I found it pretty useless. Ii compliments the Alt & Rotor. More of an indicator you take w/grain of salt.
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I velcro'd something very similar to this one to the rubber boot of my speedo on my T3. Much better than the analog veglia on my previous SP1000. http://www.aerostich.com/compact-digital-voltmeter.html
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Connections all look good, but I'll check the fuse block.
Like my airheads, I rely more on the idiot light than the gauge. With the volt meter I watch for normal or abnormal behavior - but with the thing bouncing all over the place it offers no data at all. I pretty much pay no attention to it, it's only there to fill a hole and the dash would look ugly without it.
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The Voltmeters are only as good as their connection to the wiring.
The one on my California II was inconsistent but I'm sure it was caused by the flakey connections and switch contacts.
If the Voltmeter was connected to the battery through a dedicated relay contact, not picking up stray Voltage drops it should be reliable.
On your lemans if you turn the key off and on again you will get a different reading due to the load on the ignition switch, not only that but the alternator is probably effected by ignition switch resistance also.
The Voltage seems to be measured downstream of the light switch.
It's reading what it sees, don't be surprised if its flakey LOL
Out of curiosity you could remove the fuse and jump a wire to the Volt meter side direct from the battery.
This
I've had good luck by cleaning and De Oxiting every connector hooked into the volt meter circuit. The fuse block seems to be the first to corrode for whatever reason, and is generally why the volt meter starts to slowly creep lower. I changed to a digital regulator on the AeroLario, and that helped, too.
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Connections all look good, but I'll check the fuse block.
Like my airheads, I rely more on the idiot light than the gauge. With the volt meter I watch for normal or abnormal behavior - but with the thing bouncing all over the place it offers no data at all. I pretty much pay no attention to it, it's only there to fill a hole and the dash would look ugly without it.
I don't think the voltmeter needle bouncing all over the place is related to the quality of electrical connections. I've not repaired one (only replaced with new) but the issue appears to be that the internal damping of the voltmeter needle disappears over time and mileage.
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...the internal damping of the voltmeter needle disappears over time and mileage.
If the reading was lower than it should be, then I'd assume poor connections. So I tend to agree with your analysis about damping. The Motometer VMs on the old airheads tend to do the same thing and is only cured with a new VM.
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Probably a little of each. On my 87 SPII, the gauge is inacurate as to numbers. I consider it binary. The needle either goes up when it is charging or it does not when it is not charging. Pointing to some number is irrelevant. That is until I hit the front brake switch (not the foot). When I grasp the front brake, the needle bottoms out until I release the brake lever. I suspect that is an indicator of other shoddy connections in the front of the harness and an irregular or unreliable path to ground.
Patrick Hayes
Fremont CA
So it's working well then, pointing out you have a lot of Voltage drop either in the ignition switch or Fuse 3, when you apply the front brake the current draw sucks down the Voltage at fuse 3. If you replace it with a fancy electronic one connected to the same two points it will say the same thing, don't shoot the messenger.