2003 RM 125 Stator Ohm values


8 replies to this topic
  • oldrm250

Posted October 28, 2010 - 07:33 PM

#1

Bought my son an RM125 the other day. Guy said "it screams." Well, if all I have to replace is the stator unit then it wasn't such a bad deal. It has no spark and no voltage at the source. I pulled out the stator and took some readings.
Resistance on coils 26.7 Ohms and resistance on Pick up is 106 Ohm. Can any one tell me what they should be? 2003 RM125

thanks

  • oldrm250

Posted October 29, 2010 - 07:06 PM

#2

ok, I still can't find the Ohm values for this RM 125. So, I decided to go ahead and use this stator unit again. It's not shorted out- there's no resistance between the low or high tension and earth. I polished the tops of each pole, removed the old solder connections which were very weak, fresh solder, covered any exposed wire on the stator. Cleaned the ground wire connection to the assembly.

Also test the kill switch and it's good. For those that don't know how to test it you can simply unplug it.

Ohm test improved resistance by .7 ohm

Tomorrow I'll reinstall the old stator and reconnect everything using di-electric gel.

We'll see what happens tomorrow. Ordered a Service manual on Ebay too.

Edited by oldrm250, October 29, 2010 - 07:11 PM.
add


  • oldrm250

Posted October 30, 2010 - 07:25 PM

#3

It works awesome. A big smile over my face when I went for an AC output test on the stator. My son kicked it over and I saw 11, 14, 17 volts. For those with stator issues-if it's not shorted out, it's probably still usable. I got lucky today. Also, I used loctite on the screws inside the housing for extra security.

The key here was re-soldering the stator to the harness. I noticed the manufacturers solder connections were weak- my ohm reading was going up and down while I wiggled the wires during testing.

Total repair cost $ .50 ( 1 roll of black electric tape)

Also, I used plenty of dielectric gel thus making most of my connections waterproof and less likely to arc. Good luck.

  • Kio

Posted October 31, 2010 - 05:21 AM

#4

Maybe too late, but if you still want the values:
coils resistance
Red/white-black/red 18-30 ohm
green-red 75-125 ohm

Your values are right.
If you want I have also the manual for this bike.

I have a 92 rm 125 and two different stators (the original and a brand new), I took this readings:
original 3,9 Mohm, pick up 104 ohm
brand new 127 ohm, pick up 103 ohm

But there is no spark with all of them. Can you explain to me how you test your electrical system? Should the values be similar to yours?
Can be the ignition coil? Thanks

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  • oldrm250

Posted October 31, 2010 - 06:16 PM

#5

Ok, you have a new stator and still no power? I would install the new stator and rotor. Kick that motor over while running an A/C test. Don't connect anything else (no harness, no CDI, etc). To test for voltage, set your meter to ACV. Test the wires coming out of the (stator COIL), ignore the ground and ignore the pick up. Plug your tester into those two wires coming out of the coil, it doesn't matter neg or pos. If this makes no sense, Google " how to test Stator Coil" Nice little You tube lesson.

Resistance check:
Check the two leads ( each ) to the ground, If you have any value at all, that's not good.

Make sure the ground is absolutely clean. It's on the stator housing. Disconnect it and hit it with 400-500 grit sand paper.

Arcing- leave nothing to chance. I sealed all the wires coming out of the stator coil with RTV Silicone High temp.

I think mine was failing because of arcing- measuring resistance is no help here.

Good luck

  • Kio

Posted November 01, 2010 - 06:58 AM

#6

There is no resistanze between each wire of the stator and the ground, so it is good.
I read 14-17 volts and more on the meter, like you do, but no spark on the spark plug. So is the stator good? Probably is the ignition coil but I have also bought another one and there is no spark. Tere is only the CDI unit, but I don't have the manual to check it.
I don't know what can be...

  • oldrm250

Posted November 01, 2010 - 05:45 PM

#7

Great. You have power. Yes, the stator is good. You're almost done. You bought another ignition coil ( new) and hooked up everything including the new Stator? If still no spark, your CDI is bad. It's just a rectifier- converting A/C to D/C. Pick one up off Craig's list or Ebay.

After you fix this one, always test backwards. Unplug kill switch, Test the coil resistance, test the rectifier, test the stator.

Another way to test is with a 6 volt/12 volt circuit test lamp. Super easy and fast. One end is a clip ( ground) the other end is like a sharp as hell needle and lamp you jam into the wire. Do this while someone is cranking. It puts a tiny little whole in the wire- no big deal. You will discover power or not.

When mine died I checked it with my light test/ voltage tester and worked backwards to determine it was my stator.

So, I got lucky, I bought a 2003 RM 125 with a bad stator, new top end, new suspension, great tires, new sprocket and chain for $800.00

I've got a $1500.00 bike now- well my son does.

Good luck.

  • Kio

Posted November 02, 2010 - 12:10 PM

#8

I don't know what is craig's list, I found one on ebay but is very expensive. I want to be sure about that before buying.
Do you know if there are other models that use the same CDI? I found several RM250 and RM85 cdi at very good price.

I try to test between ground and the wire comed out from CDI (that goes to ignition coil). Do I have to test on DC or AC? After your explanation I thought on DC but there is no voltage when testing. So I tried on AC and there is only a small voltage, about 0.50v when cranking.
I think that probably the cdi doesn't work well and doesn't convert AC to DC. Can you confirm it?

I tried to use a circuit test lamp (with a 12v lamp and even with a 6v lamp) but there is
no light even if I read on the meter about 15v. Maybe I did something wrong.

You are very lucky (and smart), because you have found immediately the problem. I bought a new stator, but probably it is not the only trouble!

  • oldrm250

Posted November 02, 2010 - 05:44 PM

#9

Thanks, I'm more lucky than smart. The CDI converts A/C to D/C so you'll be testing for DC output there. The beauty of electricity is it flows much like water- it looks for the path of least resistance. Your job is to channel it.

And, you're too kind. Being from Italy, you probably have 3 or 4 languages that you can speak and/or write well. Let's see- Italian, English, Spanish, French and probably some German. Me, English and bad Spanish. (And of course the Hot Danish girl friend I had for 4 years). So, you're the smart one.

No Craig's list? Try this : www.craigslist.org

I have bought motorcycles, computers, tires, beds, remote control airplanes, bikes, etc.
Used and new. It's free and it's international. Check it out.




 
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