22's 1980 xs650 build thread

[Twenty2]

Well, maybe not plenty, but there's usually an extra unused spot in one of the multi-plug ground connections. If not, you can add a little muti-plug to make more .....

Does wire gauge matter for these voltmeters? They come with such small wires, can I just put the small wire that came with it into the ignition switch plug and same with the negative wire?

 

[5twins]

I added extensions using the normal bike size (18 ga. I think). That way I could crimp connectors on .....

Above was my 1st rendition, so I could splice into some existing power connection. But when I discovered it was giving me a lower reading than the battery actually was at, I modded it. I clipped the brown pigtail off the voltmeter red power wire and added one to the ignition switch plug.

 

[Twenty2]

I added extensions using the normal bike size (18 ga. I think). That way I could crimp connectors on .....

Above was my 1st rendition, so I could splice into some existing power connection. But when I discovered it was giving me a lower reading than the battery actually was at, I modded it. I clipped the brown pigtail off the voltmeter red power wire and added one to the ignition switch plug.

I installed the voltmeter, the power is on the brown ignition switch wire and I couldn't find an available ground spot so as of now I just pinched it under the ground for the front turn signal. With key on I'm getting 11.8 or 9 volts at the voltmeter but I'm getting 12.25 Volts at the battery.... I also get 12.65 at the battery with the bike completely off. So about a .35 volt drop between battery and voltmeter, is there an explanation for this? Is my temporary ground location causing the difference? Or is this normal and I'll just always assume the voltmeter is .35 low?

 

[Jim]

a .35 drop coming out of the ignition switch is something you'd want to fix. But first, use a known good voltmeter and measure at the point you hooked up your new meter. You need to determine if the new voltmeter is just reading low or if you're getting a drop across the iggy switch.... or a combination.

 

[Twenty2]

a .35 drop coming out of the ignition switch is something you'd want to fix. But first, use a known good voltmeter and measure at the point you hooked up your new meter. You need to determine if the new voltmeter is just reading low or if you're getting a drop across the iggy switch.... or a combination.

So with the ignition on, I get 11.9 on my new hardwired voltmeter, with my multimeter attached to the brown wire at the ignition switch I also get 11.9..... so seems like my voltmeter is all good, I had tested it against my multimeter previously before installing it and it was pretty bang on. When I put my multimeter on my battery with the ignition on I get 12.2 or so... the voltmeter only goes one decimal place so I'll round down the multimeter. So between the battery and the voltmeter I get a drop of about .3 Volts, is that too much?

 

[Jim]

So with the ignition on, I get 11.9 on my new hardwired voltmeter, with my multimeter attached to the brown wire at the ignition switch I also get 11.9..... so seems like my voltmeter is all good, I had tested it against my multimeter previously before installing it and it was pretty bang on. When I put my multimeter on my battery with the ignition on I get 12.2 or so... the voltmeter only goes one decimal place so I'll round down the multimeter. So between the battery and the voltmeter I get a drop of about .3 Volts, is that too much?

That's borderline. What happens is the regulator looks at that voltage coming from the iggy switch to determine battery voltage. If what it's seeing is low, being just a dumb box, it assumes that's what the battery charge is.... low. So it overcharges the battery. .3 volts over isn't terrible... but it will only get worse.

 

[Twenty2]

That's borderline. What happens is the regulator looks at that voltage coming from the iggy switch to determine battery voltage. If what it's seeing is low, being just a dumb box, it assumes that's what the battery charge is.... low. So it overcharges the battery. .3 volts over isn't terrible... but it will only get worse.

Any issues with me riding for the rest of the season? Probably only only another month tops.
What would my next test be? To see why the iggy is .3 low?

 

[Jim]

Any issues with me riding for the rest of the season? Probably only only another month tops.
What would my next test be? To see why the iggy is .3 low?

No, won't hurt a thing as long as your battery isn't overcharging. Rev the bike to about 3500rpm and check the voltage at the battery and tell us what it is. As long as it's under 15V you should be fine.

First step in fixing it is to clean the contacts on the switch. Hopefully 5twins will chime in here with his excellent pics on the iggy switch.

 

[LTGTR]

Jim - I read a lot on the forum about voltage drop and members wondering where its happening. I wonder if it would be worthwhile to show/demonstate how to pinpoint where, and how much, voltage drop is occuring (in real time).
For example - in this thread the member is wondering if its occuring at the ignition switch - why not measure the voltage drop only across the ignition switch. As you know this can only be measured while current is flowing in the circuit and what you are measuring is the amount of voltage that is being used up pushing a current through a resistor (the ignition switch contacts).
Its a great tool, for pinpointing the culprit, but from my limited experience the fact that current has to be flowing, to measure the voltage dropped, seems to trip up most people's understanding.
Also - there are specifications for the amount of voltage drop that is acceptable across different components, so it removes the guess work of which is the culprit.
Another good example of using this method of voltage drop is the Ducati owners who replace their battery cables with new heavier cables and report a big improvement. Why not put their voltage meter on each end of the cable and see how many volts are dropped while the starter motor is cranking. Of course the new cables are better because they have removed the old ones and cleaned the disgusting terminal on the starter motor and put on a new cable with a clean terminal and done the bolt up nice and tight (you get the picture).
For all the people on this forum that are involved in the electrics on these bikes, I think its a great tool.
Regards Ray.

 

[Jim]

Jim - I read a lot on the forum about voltage drop and members wondering where its happening. I wonder if it would be worthwhile to show/demonstate how to pinpoint where, and how much, voltage drop is occuring (in real time).

With regards to the regulator, I've done a video showing how and where to check for voltage drop. It's in comment 3 of my Rotor page here.
I agree, a larger discussion of voltage drop in general would be useful. Haven't looked, but I suspect there's several Wiki pages that could be drawn from.

 

[Twenty2]

No, won't hurt a thing as long as your battery isn't overcharging. Rev the bike to about 3500rpm and check the voltage at the battery and tell us what it is. As long as it's under 15V you should be fine.

First step in fixing it is to clean the contacts on the switch. Hopefully 5twins will chime in here with his excellent pics on the iggy switch.

Here's what I've found....
At idle, 1100-1200 rpms....
Approx 13.2 at the battery and at the voltmeter

At 3500-4000 rpms
14.5 at the battery and at the voltmeter..... at the battery the multimeter did flash 14.52 for a second

Can we make any conclusions from this?

Picture is of voltmeter but multimeter was the same I just didnt have a 3rd hand available.

 

[5twins]

Yes, checking the voltage into and out of the ignition switch right at the switch is probably the best. I suppose it's possible some voltage loss is occurring on the main power feed line from the battery, most likely at the fuse, especially if the fuse holder is the original.

But, if you wanted to clean the switch contacts, luckily they're easy to get at. They're the 1st thing you'll see when you split the switch housing in half. Remove the two screws from the base .....

..... and the upper round black housing that holds the key cylinder will come off, revealing the contacts .....

The white plastic piece with contacts can be pulled off it's post for easier cleaning .....

..... and the detent plate underneath can also be lifted out .....

But you really should consider disassembling the whole thing and servicing it. Most have never been cleaned and lubed since they left the factory, and it's time they were. Here's a recent thread that covers it pretty well. Eventually I plan to write one but I'm still gathering info .....

http://www.xs650.com/threads/ignition-switch-repair.60639/#post-712497

 

[YamadudeXS650C]

Here's what I've found....
At idle, 1100-1200 rpms....
Approx 13.2 at the battery and at the voltmeter

At 3500-4000 rpms
14.5 at the battery and at the voltmeter..... at the battery the multimeter did flash 14.52 for a second

Can we make any conclusions from this?

The numbers you are getting are quite healthy. You are charging well.

 

[Twenty2]

Yes, checking the voltage into and out of the ignition switch right at the switch is probably the best. I suppose it's possible some voltage loss is occurring on the main power feed line from the battery, most likely at the fuse, especially if the fuse holder is the original.

But, if you wanted to clean the switch contacts, luckily they're easy to get at. They're the 1st thing you'll see when you split the switch housing in half. Remove the two screws from the base .....

..... and the upper round black housing that holds the key cylinder will come off, revealing the contacts .....

The white plastic piece with contacts can be pulled off it's post for easier cleaning .....

..... and the detent plate underneath can also be lifted out .....

But you really should consider disassembling the whole thing and servicing it. Most have never been cleaned and lubed since they left the factory, and it's time they were. Here's a recent thread that covers it pretty well. Eventually I plan to write one but I'm still gathering info .....

http://www.xs650.com/threads/ignition-switch-repair.60639/#post-712497

I am using the original fuse box... is there a way for me to test if it's causing the .3 volt drop at the ignition switch?

 

[Jim]

For a suspected charging issue, My opinion is it's best to check voltage drop on the brown wire at the regulator itself. The contacts at the switch could be just fine and you could still not have correct voltage at the regulator. On your '80 for instance, from the iggy switch the power goes to the fuse box and out on another brown wire... that's a possible place for high resistance and a corresponding voltage drop. From there it goes through 3 more splices before it arrives at the regulator. So, that's 4 additional sources for problems. Granted, it's usually the iggy switch causing the voltage drop, but I have seen the fuse box cause drops as well. I think it's best to start at the regulator and work your way back if there's a problem.

RE your readings: yes, those charging voltages are fine.

 

[5twins]

In post 171, you're not reporting the .3 volt drop anymore? To test the fuse, measure voltage going into and coming out of it.

When I get one of these, one of the first things I do is go through and inspect and clean all the wiring and connections. I start at the tail light and work my way forward up to the headlight. On my '83, I found the plugs for the reg/rec and ignition black box badly corroded, to the point where I even had to replace a couple of the crimps in the plugs. These two connectors are in a bad spot, on the left side of the battery box. They can get exposed to battery acid and battery acid fumes. I assume that's what happened to mine.

 

[Twenty2]

For a suspected charging issue, My opinion is it's best to check voltage drop on the brown wire at the regulator itself. The contacts at the switch could be just fine and you could still not have correct voltage at the regulator. On your '80 for instance, from the iggy switch the power goes to the fuse box and out on another brown wire... that's a possible place for high resistance and a corresponding voltage drop. From there it goes through 3 more splices before it arrives at the regulator. So, that's 4 additional sources for problems. Granted, it's usually the iggy switch causing the voltage drop, but I have seen the fuse box cause drops as well. I think it's best to start at the regulator and work your way back if there's a problem.

RE your readings: yes, those charging voltages are fine.

The charging is good but the voltage drop is still a charging issue? If it's charging fine when running, what damage will the voltage drop cause when the bike isn't running? I don't want to start taking things apart unless I need to.

And just so I'm clear, should the voltage at the iggy switch be the exact same as at the battery? Or should it be slightly less?

 

[Twenty2]

In post 171, you're not reporting the .3 volt drop anymore? To test the fuse, measure voltage going into and coming out of it.

When I get one of these, one of the first things I do is go through and inspect and clean all the wiring and connections. I start at the tail light and work my way forward up to the headlight. On my '83, I found the plugs for the reg/rec and ignition black box badly corroded, to the point where I even had to replace a couple of the crimps in the plugs. These two connectors are in a bad spot, on the left side of the battery box. They can get exposed to battery acid and battery acid fumes. I assume that's what happened to mine.

The .3 drop happens at the iggy switch when I turn the key on, before I start the bike. Once the bike is running the voltage at the battery and the iggy switch is the same.

 

[Jim]

The .3 drop happens at the iggy switch when I turn the key on, before I start the bike. Once the bike is running the voltage at the battery and the iggy switch is the same.

There's been some confusion among some members here as to what a "voltage drop" actually is in this context. So...

A voltage drop has nothing to do with key on/key off scenarios, or engine running vs not running... put that out of your mind. Voltage drop is simply a comparison of the voltage applied to a component vs the voltage coming out the other end... so this check is always performed with the key on.... never off, or off vs. on.
So, let's look at a switch. If we apply 12v to the switch and measure 12v coming out of it, the voltage drop is said to be 0.
If we apply 12v in and what comes out is 11.7, the voltage drop is .3v. In other words, there's resistance built up on the contacts causing a power loss. In this case, three tenths of a volt. This is all a voltage drop is... full stop. nothing to do with turning the bike on and off.... or engine running or not.

Think of a fuse in the same way. Where the fuse plugs in is the same as the "contacts" on a switch. It's a "contact" point, made to transfer power. Built up resistance there will do exactly what it does to the switch... cause a drop in voltage. And finally, a splice will act the same.

 

[5twins]

If, once running, the voltage coming out of the ignition switch is the same as going in (battery voltage, then you shouldn't have an over-charging issue. That occurs when the voltage coming out and being fed to the regulator is lower. Then the regulator thinks the battery is low so it increases the charging output. But, the battery isn't low so it gets over-charged.

Sounds like your ignition switch may be just a little dirty inside. You'll probably be fine with it for the rest of the season but I'd put a switch cleaning on your winter "to do" list. Actually, you should service all the locks (seat and gas cap). I'm sure they could all benefit from a clean and lube.