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Discussion Starter #1
I own a 1990 750 Vulacn 17,788 and still counting. I just purcahed a brand new sealed battery for my bike and my bike is dieing quickly.

What can cause it to die quick being I just brought a new battery?

Mind you my headlight switch is jammed on HIGH BEAMS meaning as soon as I turn on the bike the high beams are on and always on. Can that cause this problem?

Also I put the battery on the charger mostly every night once I bring in the garage from riding and I leave it over night or when ever till the next time i ride.

So with that being said what can cause this problem and how can I fix it?
 

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It could be your charging system is at fault. Check the stator AC output with a multi-meter. Believe the procedure is in the manual.
 

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Hows it going? If you have a multimeter you need to remove the seat and with the bike running at 3000-4000 RPM's measure the voltage across the battery. You should have close to 14 VDC maybe a bit higher. Anything over 15 VDC you may have a bad R/R. If you have batterty voltage 12VDC and you can see this value decrease as the bike is running then you have a charging system problem.
If thats the case you need to inspect the wires going to the R/R and also check the grounds, One on the engine case and one next to the Neg terminal of the battery. in fact it goes to the neg terminal of the battery.
The Second step would be to do continuty checks of the stator. The 3 yellow wires on the R/R plug are your stator wires. Unplug the R/R and check each one to ground. You should have NO continuity. Then check each wire to another. Mentally lable them 1,2 &3. Check 1-2, 1-3, & 2-3. you should have 1-2 OHMS resistance for these readings.
Let us know what you come up with.
 

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Just curious what charger you are using? I read somewhere that older battery temders are not good to use on AGM batteries.
Of coarse, this would not explain why your battery is low in the first place.

If you are running your high beam at idle, you could be draining the battery. Is the physical switch stuck or is it always using the high beam (which could be a result of the reserve lighting control) is the low beam part of the bulb burned out? That would cause the system to turn on the high beam.

Check your charging system as stated by the others, but search for Stator test as well as testing the R/R output.

Good luck! let us know what you find.
 

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Giggity!
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Check my signature for the repair manual to download. You can read up on all the issues & how to fix them. To check your bulb remove the two small screws on each side of the headlight housing at 8 & 4. With them removed you can remove the headlight & check you filliment in the bulb visually & see if one is broken.
 

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Discussion Starter #6
Okay so I took you guy's advice, I did some testing on some of the electrical components on the bike and my readings are not coming back correct. I just ordered a voltage regulator and a starter solenoid relay. Once I get these part's I hope this will fix my problem.

Thank You If you have more suggestions or answers please let me know
 

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What readings did you get, and what did they indicate? Replacing the regulator/rectifier on a bike with a bad stator can lead to failure of the new R/R.
 

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Linkmeister Supreme
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Just curious what charger you are using? I read somewhere that older battery temders are not good to use on AGM batteries.
Of coarse, this would not explain why your battery is low in the first place.

If you are running your high beam at idle, you could be draining the battery. Is the physical switch stuck or is it always using the high beam (which could be a result of the reserve lighting control) is the low beam part of the bulb burned out? That would cause the system to turn on the high beam.

Check your charging system as stated by the others, but search for Stator test as well as testing the R/R output.

Good luck! let us know what you find.
I can`t find the reference in the verses or the Clymer manual right now, but I think the reserve lighting unit only switches on the remaining headlight filament once, when the first filament initally burns out. Once the headlight hi/low switch is moved back and forth or the bike is turned off and restarted, the reserve lighting unit doesn`t automatically switch to the remaining filament.
 

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X2 with Flitecontrol, You need to check that stator. You can burn out the new R/R. The input to the R/R comes from the stator so if its bad the output will not be correct. What kind of R/R did you order?
 

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Valkyrie Riding Member
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Alright y'all...

I am having a similar issue with my '86, so I am posting here instead of starting a new thread.

I just replaced my Stator and Battery. (I actually dropped the engine to do it right) The bike ran great all day, then BAM. Battery dead. I haven't yet replaced the R/R so I'm thinking that I may need to do that.

We got this bike as a POS for $100 and have just been cleaning and building on it. It's one of those, 'It looks so bad that it looks good' bikes.

I'm going to put meters to it again tonight, but wanted to get opinions.
 

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1986 VN750
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Alright y'all...

I am having a similar issue with my '86, so I am posting here instead of starting a new thread.

I just replaced my Stator and Battery. (I actually dropped the engine to do it right) The bike ran great all day, then BAM. Battery dead. I haven't yet replaced the R/R so I'm thinking that I may need to do that.

We got this bike as a POS for $100 and have just been cleaning and building on it. It's one of those, 'It looks so bad that it looks good' bikes.

I'm going to put meters to it again tonight, but wanted to get opinions.
Since you already did the hard work, it is most likely the R/R. Test your new stator (search the forum for the procedures), and test your R/R. I am betting you'll find the R/R is toast, since you have a new stator.
 

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When checking the charging system, start with the bike off, and check across the battery terminals. You should get around 12V-12.5V. Start the bike up and let it run at idle. With the headlight on, your voltage reading should drop some, down to 11.5V or lower. What that means is the charging system is not producing enough current to keep up, and the battery is slowly discharging. Now rev it up to around 3000 rpm and check the voltage across the battery terminals. You should get around 14V, definitely over 13V. if so, the charging system is working.

If the voltage does not come up, something is wrong. If you know the battery is good (and new does not necessarily mean good, I have seen several brand new batteries that were no good and would not charge), then start at the beginning before replacing any parts. Check the stator. Yes it's a pain to replace, but if it's bad, nothing else is going to fix the problem. IF the stator checks out good, make sure the wiring to the R/R is good. You should have already found the three bullet connectors in the yellow wires coming from the stator. Check them for any heat damage at all. If you find hardened and/or discolored insulation, you have a bad connection at those connections. As a temporary fix, cut the connectors out, get some more wire of the same gauge, and splice them together, using screw on wire connectors (wirenuts) to make all connections. Now check the voltage at the battery again. If it is still low, and all connections are good, including the battery to frame and frame to engine ground connections, it is almost certainly the R/R.

I don't know why you ordered a new starter relay, were you having problems with it? Bear in mind that the relay requires sufficient voltage to work. The relay also has nothing to do with the charging system. I have rarely ever seen one fail, but as with anything else it is possible. It is easy to test though. Just apply the correct voltage to it and it should click, and (with both the battery cable and starter cable disconnected), you should get continuity across those two terminals when it does.

I have seen many trained professional mechanics start throwing parts at a problem, believing they know what is wrong, and it often winds up being the last replaceable part causing the problem. At least they now have a whole new system, but it is an expensive way to fix something.
 

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Linkmeister Supreme
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Alright y'all...

I am having a similar issue with my '86, so I am posting here instead of starting a new thread.

I just replaced my Stator and Battery. (I actually dropped the engine to do it right) The bike ran great all day, then BAM. Battery dead. I haven't yet replaced the R/R so I'm thinking that I may need to do that.

We got this bike as a POS for $100 and have just been cleaning and building on it. It's one of those, 'It looks so bad that it looks good' bikes.

I'm going to put meters to it again tonight, but wanted to get opinions.
Is the new battery an AGM-MF style? (sealed)
Will it be charged up after a night on the charger?
You do know that the charger you use should be no more than 10% of the battery`s capacity. Using a high capacity automotive charger will overheat the lead battery plates and warp them, causing a dead short. Our batteries are rated at 14 or 15 ampHours, so your charger would ideally charge at about 1.5 amps to no more tham 2 amps.

When you get the engine running, does the headlight get brighter when you rev it up?
That`s a crude, but quick and easy charging sytem check.
 

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I can`t find the reference in the verses or the Clymer manual right now, but I think the reserve lighting unit only switches on the remaining headlight filament once, when the first filament initally burns out. Once the headlight hi/low switch is moved back and forth or the bike is turned off and restarted, the reserve lighting unit doesn`t automatically switch to the remaining filament.
my bad!.. thanks for the clarification on that.... :beerchug:
 
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