Best electrical layout?

So I just bought a 1981 Yamaha xj550 Maxim and am having an electrical problem.
The guy I bought it from said I would probably need a trickle charger for the battery, but I do not want to have to charge the battery every time I want to start it. Supposedly this battery is new, but it goes dead really easy and I do not want to get caught outside of my garage with a dead battery. What is the best setup for my bike? Can I get a stronger battery? Tweak the ignition or starter? Any advice or tricks will be greatly appreciated.

 

If you're battery is not holding a charge, check your charging system..
Either you have bad brushes on the alternator or your regulator/rectifier is toast.

put a meter on your battery, start the bike and get the revs up over 2K, you should show around 14 V or so +/-

 

My approach would be to try to fix what's wrong first. I have the same bike you have and, with a new battery, I never run short on cranking power even after sitting a couple of weeks.

First you need to determine if there is a drain on the battery causing it to go dead or if the battery is bad (even a new one can be).

Try disconnecting the battery and charging it. Check after a day or two to see if it's still up.

Depending on what you have for epuipment you may be able to identify a drain by disconnecting the negative battery cable and putting a voltmeter between the nagative battery post and the cable. If it reads any voltage (with all the switches off) then you have a drain someplace. You can do the same thing with an ammeter but most hand-held multimeters can only handle a fraction of an amp and are easily ruined. If the drain is bad enough you may even notice some arcing when you desconnect the cable.

If you determine that you have a drain then it's a matter of chasing circuits until you determine where it is. You might start by disconnecting fuzes one at a time to see if you can identify which circuit is the problem. As long as you're at it, folks here recommend changing out the fuze box for one with blade style fuzes as the original setup is a common cause of problems.

Stick around, there'll be plenty more suggestions.

 

...or a couple of other possibilities... one of which is the infamous 8-pin connector between the regulator and the alternator. I'd been concerned that, while my battery didn't run down, I also didn't see much over 12V even at 4000 RPM. I pulled that connector out yesterday and found that the connectors for the red wire were a bit melted and a bit burned up. I pulled those connectors out, cleaned them up, tightened the female connector, put some dielectric grease on, and put things back together... now hitting 13.5V or so from 2K on up.

 

Thanks guys, all great advice. I am going to buy/track down this equipment and start. Will post results.

 

I charged the battery and it cranks fine and chugs beautifully.... with no turnover. I left the bike off (no keys in it) and put the voltmeter between the 2 battery posts and got a reading of about 15-20v. I checked again after removing the fuses 1 by 1 under the seat and the reading was the same.

I'm assuming the problem is still electrical as it runs fine with a push start. Do i go in for a look at the charging system or look for a short or something else??

 

"you may be able to identify a drain by disconnecting the negative battery cable and putting a voltmeter between the nagative battery post and the cable."

possibly a noob question but there is a reading when both cables are connected. Not a reading when I did what Johntc said...Mean something?

 

You are looking to see if the bike is sucking any power at all, just sitting there. It doesn't matter if you check from the - terminal to the ground cable, or the + to the red wire.

When both cables are connected- - what are you reading??
You should have 12.4 across the battery.

 

Well, first of all, 15 to 20 volts on the battery is too high. I'd be concerned about that. It really shouldn't be over 14 volts at the battery with the engine running and revved up. With the engine off, probably 13 volts or so max at the battery.

Second thing is, what voltage do you read between the red/white and black wires on the TCI module when cranking? This is the voltage that the coils are getting, and if that's less than 9.5 volts or so, I could see you having problems getting good spark.

A lot of electrical problems relate to high resistance somewhere. When there's no load, these problems can't be "seen" with a meter, because they aren't dropping any voltage. When you add load, like by cranking the starter, that's where you reveal problems like this. For instance, a lot of bad batteries will read just fine (12.5V or so) until you hit the starter, then they'll drop right down to a few volts while cranking.

 

When checking for a minor drain like that, you need to get a DMM, and set it to amps. You could use an analog ammeter here, but we're looking for drains in the milliamp range.
Undo one of the battery cables (I prefer the positive one myself) and place the leads on the battery terminal and the cable eye. Hopefully you get 0, that means you can focus on the charging system. While you're here, so to speak, do a voltage drop test between the positive terminal while its hooked up to the battery. Set the meter to volts, one terminal at the eye on the battery, the other on the terminal at the starter, then at the fuse block and alternator.
Watch for voltages during cranking, and then during normal operation. You shouldn't see more than .05 running, or .1 to the starter during cranking. Any higher means there's extra resistance somewhere.

Also, you said you got a really high reading from the battery. Was this right after it got done charging? A voltage that high usually indicates a sulfated battery, which itself is caused by constantly being undercharged. Sulfated batteries have a good deal more internal resistance than a good battery, and can put extra load on the charging system. They also won't hold a charge nearly as well.
If this is the case, you're gonna have to get a new battery.

Typically with the engine running at a good clip, you should see something like 14V between the battery posts. Might be higher or a touch lower, I'm not really sure what the regulators on these bikes are set at. If it's abnormally low, either the alternator is defective somehow, or there's a heap of resistance in the charging circuit somewhere. If it's high, the regulator isn't controlling the alternator right, and its overcharging your battery.

I could go on and on... but let's start with that battery first, then move on...

 

Were's the best place to get one of thiese DMM's, because the 1980 XJ650 i just got does that, yeah the guy i got it from left the bike sit outside all the time and did'nt take very good care of it. Had to jump it from my jeep, and it started up, got it home, got a new battery for it. The bike started up all day, but was dead the next mornong.

I've got my new Glow when blown fuse box, and im ordering a new manual this week.

 

A DMM is just shorthand for digital multimeter. Off the top of my head, I know craftsman has a ton of them, ranging from $30 on up.

I'd highly recommend an auto-ranging multimeter, they're pretty nice to have when you're not sure what settings to use. The downside is they usually start at $80 or so.

I'm pretty sure you could find them at any place that has a wide tool selection, like lowes or home depot as well.

 

Gotcha, Yeah the wireing system never was one of my strong points. The turn signals wouldnt work on my bike when i got it, nore would the brake light, which means i've got my work cut out for me.

 

OK. After, to no avail, doing many tests on the electrical system I decided to try and start the bike in 1st with the clutch in (obviously) and kickstand up. It worked. I had always been trying to start her in neutral. This leads me to believe there is a problem with the neutral safety system, but there are other symptoms.

After she fired up none of the indicator lights work, except for the red oil check one. This one flickers on start up. The neutral light does not light up when i am in neutral.

Turn signals and horn no longer work. Same with the brake light, which is always on.

The headlight works, but this is not in the original fuse box. The previous owner used a plastic tube that holds the fuse. This is connected to the appropriate side of the fuse box. (not sure what this is called.) The bright switch also works.

So....I don't know what i should start looking at to make her street legal. All of the stuff that doesn't work now used to work.

One last thing. My battery reading was approximately 12V when it is off and dropped to about 8v on start up. Obviously a drain wasn't the problem, but my initial reading was off due to my analogue VM. I also checked the amps like Bobcharles said. I got a fat 0 on this test.

 

12V is low for no load, it really should be like 12.4~12.6V. Dropping to 8v when cranking also isn't very good, it really shouldn't get much under 10v.

Sounds like your battery is either undercharged or bad.

Doesn't explain the rest, though... sounds like you have a lot of electrical gremlins!

 

Its been a while, but I thought I would give an update, maybe it will help some noobs like me.

1. If your fuse box is anything but beautiful, replace them with inline fuses. Because some things would work sometimes, and other times not, I could not identify the drain. I was looking for an electrical problem all over the bike assuming it was not the fuses because they did not look too bad, I was wrong.

2. Rectifiers can have histories you wont know until you buy the bike. Mine was shot, but the bike would still start, sometimes. Considering how much of a pain these electrical problems were, next time I buy a bike, I'm bringing a voltmeter.

I'm not sure if it was the rectifier or the short draining the bike, but they are both fixed, and I no longer need to disconnect the battery every trip!

 

We all preach the "replace the fusebox now" gospel around here

Reg/rect can be fun, I fried my own (check your grounds people, be sure they are tight) after that, battery wouldn't charge at all, got one from one of the guys on here that had a parts bike.

If the reg/rect was gone, then anytine you ran the bike the wole electricl system would be draining the battery, + if you had a short as well, would be an evil combo.....

 

I saw a basic chart on here at one time. I tried to search for it but had trouble finding it.