1980 xs 400 charging

[firegatejeeyamaha]

Ok i am not having much luck with my bike i am trying to to find out why the battery wont hold a charge and what is draining the life from the battery.

What i have tried I have used a volt meter and checked battery with key off and it says there is like 12.1v then i turn key on and it goes to 8volts and 7volts.

Not sure if this is like a car at all but on a car you are able to take the battery out after the car is running and it will still run so i gave that a try started it up then disconnected my battery and then it just dies. Not sure if this is normal or what.

So if you guys give me some advice on how to check to see if the stator is giving out the juice and the right amount of it.


Thanks

 

[Ringo]

These bikes need a battery to run. And the their charging system is pretty terrible so if you don't start with a fully charged battery, it'll just keep going downhill. I believe it was drewpy who told me it takes these bikes something like 15 minutes of riding to gain back the lost charge of starting it. So if you're just doing short rides you'll kill your batt pretty quick, unless you're using the kickstarter. There are things you can do to help lighten the load on the electrical system too- like a 35w h4 headlight bulb, LEDs, etc.

 

[firegatejeeyamaha]

I have only been kick starting it nothing else i can let it sit for a bit but then the volts just start to die down when it is idling and when it hits 7.77 or so it dies out do you know how to test the stator and regulator

 

[Ringo]

You could get a voltmeter. Do you have a battery charger? Maybe try charging the battery fully and seeing how she runs.

 

[firegatejeeyamaha]

Well i do have a battery charger she runs good when it is connected and then i disconnected and it still runs when i have the volt meter on it at idle it starts off at 13volts or so and starts to go down and then hits 7volts and dies but when i give it gas it goes between 13.94 and 14.21 what would let it charge when i am on it and not let it charge during idle

 

[Ebola Monkey]

These bike charge for shit at idle.

If you don't start with a KNOWN GOOD, FULLY CHARGED battery, you'll be beating your head against the wall.

If you're doing a lot of idling, and or signaling/braking you'll drain the battery fast. The charging system in my cs400 all checks out OK to specs, has a good battery, has a second ground to the chassis, but is still a pin in the ass.

The battery is tiny, so it doesn't hold much reserve, and the output is really close to the draw of the bike.

 

[Travis]

Sounds like a bad battery.. I would replace that first with a new battery that has been fully charged.. then check to see if you have charging problems.

Edit: Looks like Ebola Monkey beat me to it!

 

[firegatejeeyamaha]

from the time i start the bike it will last 2 mins at the most unless i am on the gas it should last longer then that no matter how shitty the battery is but i am going to try a new battery as i am sure it could not hurt anything to just replace it

 

[Travis]

I don't know... the charging systems needs power to make power. You need voltage to even activate the rotor which is basically an electromagnet. If these charging systems are weak like people are saying, it would probably die with a bad battery.

Replacing the battery will definitely not hurt anything, especially if it goes to 8 volts by just turning the key.

 

[drewpy]

you need a good 12v/amperage to excite the field coil which in turn creates the necessary magnetic energy to create the voltage for charging the battery. If it has electronic ignition there's even more reason to have a good 12v.

the output is regulated via the voltage reglator (either mechanical or electronic) to the feild coil. a duff battery will give diminishing returns fairly quickly as to what you are experiencing.

 

[hardtailed77]

Another really simple point to add.... If you decide to purchase a new battery, MAKE SURE you follow the directions that come with the battery involving how to initially charge it and the amount of time required to do so. I'm not a big directions guy, and know little about batteries. I paid $40 for a new one and only charged it for a few minutes before putting it in the bike (battery read fine when I charged it for that short time). BIG MISTAKE!!!....which ended in me ruining a brand new battery! Over the span of about a week, the battery was useless, even after many attempts to recharge it. Just a word of easy advice. Good luck

 

[4 a yamaha mech]

Ok i am not having much luck with my bike i am trying to to find out why the battery wont hold a charge and what is draining the life from the battery.

What i have tried I have used a volt meter and checked battery with key off and it says there is like 12.1v then i turn key on and it goes to 8volts and 7volts.

Not sure if this is like a car at all but on a car you are able to take the battery out after the car is running and it will still run so i gave that a try started it up then disconnected my battery and then it just dies. Not sure if this is normal or what.

So if you guys give me some advice on how to check to see if the stator is giving out the juice and the right amount of it.


Thanks

Bathurst, NB. Canada,, July 15,2012.. Hello,, Many years ago everybody used generators that put out 6 volts or 12 volt DC and need a heavy cut-out control box with points etc. The whole thing worked OK but wore out easy and often needed adjustments.. Finally the altenator was invented but it only produced alternating current that increases as the speed of the engine does and you need a rectifier to get DC and also a regulator. These are two seperate items but now are often combined so if one breaks you have to buy one expensive part unless you can modifiy something. All these solid state items rarely break but to be on the safe side YOU MUST NEVER DISCONNECT THE BATTERY WHILE THE ENGINE IS RUNNING. THE BATTERY IS A SHOCK ABSORBER .WHEN THERE IS NO BATTERY THE ALTENATOR MAY SEND EXCESSIVE CURRENT TO THE RECTIFIER AND DESTROY IT. THIS APPLIES TO ALMOST ALL ALTENATOR SYSTEMS ON BIKES OR CARS. Chain drive bikes can sometimes carry odd things in and cut some wires. I don't know how to check a regulator but rectifiers are pretty easy to check and the other fields or rotors are easy to check but you will need the books with correct spects, and you need an OHM meter and have to learn how to use it. Also check to make sure there are no grounds.

 

[domains]

4 a yamaha mech... i'm in bathurst small world

I got a 400 il sell you when summers over only 18000 on it


Red wire coming out of regulator charges batt

 

[francois]

i have a xs 400 yamaha and it is not charging at all. what is the specs on the alternator and where can you still get spares for it.

i am from South Africa.

thanks
karel