2002 zx12r battery keeps goin down, replaced stator regulator and battery ran for about a month and same thing happened again. what could be the problem?

Sounds very much like the starter motor relay. Try the old trick of putting a screwdriver over the contacts..

cant test the regulator.....test the alternator...stator and roter make up the alternater...cant test the roter...its a magnet......test stator by unplugging it and put a test lead in 2 of the 3 conector terminals and then rotate 2 more times to test all...1-2,,,,1-3,,,,,2,3.......should get about 40 VAC...volts ac.....i bet one test will be low....below 20....replace stator...if test is good.....now do the same test but use ground instead of one of the lead terminals...check with ohms/resistance.....as long as all readings are OL...replace regulator...

ofcourse sir , this all happens when regulater get shorted and gives over charging may harms battery ..one thing more when you continue your ride on short regulator its starts buring ur inner down stator coil...so better replace both things ..i mean rectifier regulator and stator coil...

Hi,,,if your battery is not charging and you have a rebuilt staor,,then your regulator/rectifier is the cause,,its job is to charge the battery.

Three things. The battery, voltage regulator and stator/rotor are all dependent on one another. If the battery is bad it can pull the voltage regulator and stator both down trying to keep it charged. So you need a known good battery to start, then check the output of the regulator with a voltmeter, if that is good, then it will keep the battery charged. If not good check stator output. Somewhere therein lies the problem, as they say.
The engine will misfire and run erratic because it is not getting enough electrical power to run the electronics that control it.
Bottom line, it sounds like the voltage regulator or stator is the problem, which are both easy to check.

Hi and welcome to FixYA,

Two possibilities:

• rectifier / regulator combo (most likely);
• corroded, burned, loose connection from the stator to the regulator (likely);
• faulty stator (least likely).

The stator would be producing relatively high AC voltage while revving the bike. The stator output AC voltage are fed to the rectifier / regulator through 3 white wires. Check calls for testiing for the presence of the AC voltage on any pairing of the white wires before and after the connector before the voltage regulator. Check on the regulator calls for checking the battery voltage when revving the bike (14.5 VDC).

Good luck and thank you for asking FixYa.

Common problem with poor quality parts, the regulator is the problem, the generator is working other wise you would not have fried the wiring, you answered your own question. someone telling porkies to get more money from unsuspecting client?
The regulator controls the voltage not the generator, the generator only supplys the voltage it cannot overcharge unless the regulator is not working properly, simple!

too many variables !
Firstly check battery under load ! any battery place or auto electrician can so it usually free!
do this before replacing any thing else!
make sure all connections are clean & tight
if battery is ok get them to check the charge rate on bike! its a simple test or you can do it with a volt meter they are only cheap to buy!

Hi and welcome to FixYa,

Initially, pls re-check your voltage regulator. Common/usual signs would be discoloration of the connector, burned/corroded spade lugs of connector, partial melting of the epoxy/plastic packing, the 3 same colored wires (usually yellow) looks bloated/heated up.

Good luck and Thank you for using FixYa.