Bad regulator, or alternator?

Lately, my bike has not been e-starting. If I charge battery, It will crank over well, but not fire. It will kick start. As I ride, battery charge gets lower, and will not idle, & will not even try to crank with e-start. Just a weak click. Lead battery is 2 yrs old.

With charged battery, I measure 12v across batt terminals at idle. If I rev it to about 4 or 5k, I may get 12.5 v. The WSM says this test indicates bad volt regulator. WSM also says I should get .6 ohm across 3 wires from alternator. I get .6 ohm across 2 wires, and 1.6 ohm across other 2 wires.

So, do I get to replace both?

charge your battery, disconnect it and make sure it holds a charge for a while (couple of days at least). you wanna see 12.6v or a little more with no load. probably getting close to being needed to replace it

unplug your reg and measure the voltage between each of the 3 yellow stator wires while the bike is idling (it'll be AC, I'd guess somewhere above 15-20vac); your measured resistance is okay but look at the pair that did 1.6ohms (discoloration, charred). And make sure none are short to ground. BTW there are 3 measurements: wires 1-2, 2-3, 1-3 for volts, resistance, shorts.

if it passes these two, it's your reg.

I believe '13 & '14 regulators are extra special for keyless bikes.

I measure 12v at battery, installed , dead engine. I can charge batt & have it hooked up, in bike. it will hold charge for a week or more. It is riding that kills the charge, in about 2 hours of riding.
My 3 stator wire measurements were .6 ohm, 1.6 ohm & 1.6 ohm.

So, bike will run with unplugged regulator, and not fry anything?

Yeah.

But 12v on a charged battery means its bad.

A bad battery will not take a complete charge or hold it.
Get a new and better battery.

Paw Paw

wait.
maybe your bike won't run without the stator plugged in?? the reg turns on the power relay when it detects the stator spinning *I think*.

you're not gonna harm anything though. The TC runs just fine with no battery; using the capacitor just like yours- I believe

Perhaps I should search battery theads: What modern battery is a good ( better than lead) battery? I want a life longer that 2 or 3 years, and more cranking power. I have read of some types of modern batteries burning up. Dont need that.

Earth-X or Shorai both have fans here for their LiPo batts.

you may still need a reg or stator (bad batteries take out regulators; bad regulators take out batteries. Bad stator can do both)

I disconnected three yellow wires between stator and reg. Bike will not fire with these wires disconnected. It would fire with these connected ( lately, kick start only). Apparently using power from stator to spark and inject?

What, other than a short, would knock out a stator? I have not seen any indications of shorts or heat in the wiring. If stator were bad, and battery charge way low, ( as on my last ride) would not the bike be dead, having no good power source for spark and injection? I'm trying to decide if safe to assume stator is good, thus need only new battery and regulator.

what were the voltages on the 3 wires while you had 'em disconnected (e-start may produce good enough voltage)? did you test for short-to-ground? looking for "indications" is fine, but your multimeter will tell you the score. just do it: Two 30 second tests.

the regulator does not turn on the power relay (IOW: ecu & ign & FI) until it detects the stator turning. ....I think. maybe. sort of.

if you wanna get by this, ground the wire out from the relay or just short the contacts. gotta have electricity somewhere tho (stator connected & capacitor or battery)

I had a similar issue with my 10' TE250, the stator wasn't charging correctly, so the bike was running from the battery only, and would eventually die. The stator is to provide all the running power, and the battery is for starting and acting like a "filter" to smooth out power pulses from the regulator. charging voltage should around 14VDC when running at the battery - this is normal, anything less than 13 or more than 15 = something wrong in your charging circuit.

also very important, don't run your TXC or TE ****without**** the battery hooked up or you will fry your regulator/stator. The manual is very explicit with that.

I recently had my engine rebuilt, but my mechanic couldn't get my bike to run/idle for longer than a few mins with a charged battery after a full rebuild, so long story short my mechanic replaced my stator with one from a SHERCO - not sure of the part number, I'll try and look it up from my paperwork, and the bike runs great now.

also, if your 3 wires from the stator are indicating greater than 1 Ohm, then that stator is bad from I read. I recently had mine replaced and it had grounded itself to the chassis by one of the 3 phase wires insulation getting worn away from a chassis clip, which caused it to over heat, thus melting the other leads, and making a mess, but my point is when I tested it, two of them were 1.1 OHM and the other was .9 or something.

Hope this helps, but I would think your stator is bad.

The stator wires - to ground resistance: 2.4 ohm, 2.4 ohm, 4 ohm.
E start cranking stator wire ACV: 2.5V, 2.5v, 1.5v. those numbers look low.

Reply from xlite250 says his stator was bad, with across wire resistances closer to spec than mine. So it is looking like I get to do the more expensive repair (s) .

xlite250,

Yes your info helps. It looks like I get to do a stator ( and regulator?) replace. Bad news, but good to know. Did you also have to replace your regulator?

I didn’t replace the regulator, just counting down the days, till I have to. I may end up regretting that decision. Lol

But when I checked the charging voltage it was 14.4VDC so it seemed good.

yep. your stator is shorted.

your resistance is fair, it's the SHORT TO GROUND on all 3 windings that's screwing you up.

your reg still could be bad though. when you replace the stator (2013-2014 model years only) measure your voltage when idling. if it ain't super close to 14.2v come back here with the FULL info and we'll tell you what you need to do (and don't run it too much).

save your old stator- the pick-up coil is part of it and is still good. It is not available separately OEM; you can find some KTM units that'll work.

you have a capacitor unlike earlier xlites; acts sorta like a battery to smooth & store electrical energy.

btw, you can probably get a new battery, install it and run "total loss" like you have been doing. turn the headlight off (unplug it- Or hell, just pull the dc fuse and turn off everything extraneous), kick start it and you could probably ride most of the day. recharge the battery to be nice to it when you're done.

come back and let us know how much stuff costs, part numbers etc. As always: take pictures.... for the future generations reading this.

BTW, Trench, I have a bad stator with a good pick up coil and a good stator with a bad (actually melted) pick up coil out of a 2010 TE250 can I rewire them to make one good unit?

The bad news is I suck at splicing and those wires are small!

yeah, shouldn't be a huge problem. You should not have to deal with small gauge "bell wire" of the pick-up... They have 18ga leads attached. just cut 'em long from the bad stator and splice the good pick-up into the good stator wiring harness (pull them through the oil grommet). I am thinking that polarity won't matter, but you might as well match it up. hell, you may be able to cut the terminals off and pull the wire all the through then add new terminals after mating with the good stator.

to tell you the truth, I'd just hold on to both stators and do the fix in the future. Or really- just put the good pick-up and the good stator on the shelf separately- for the proverbial rainy day.

Polarity of the pick up coil may or may not matter but why not get it correct . A friend of mine bought a Kx 250 that wasn't running and someone had tried replacing the pick up coil . The no spark was a bad plug cap . While trying to kick start it the kick start shaft snapped . He bump started it and it ran very poorly , couldn't get it past 1/2 throttle . He replaced the kick start shaft thinking it may have been weak . 3 kicks later the new kick start shaft also snapped in the same spot . This time we pulled the flywheel and noticed the new pick up coil . I reversed the polarity from what it was and we bump started the Kx . Now the 's ran as it should , started easier and sounded much healthier . He then replaced the kick start shaft again and it hasn't snapped since . On THIS bike it seems that the wrong polarity of the pick up coil caused the timing to be off enough to cause the kick start shaft to snap while trying to kick start this gem . Will the wrong polarity on the pick up coil do this on other machines ? I don't know but why risk it .

Yep, that's what I said. It may be a the falling edge of a pulse or the rising edge that's the trigger- so why chance it?