Need electrical advice on YTM225DX

[Doc Holliday]

Okay...got a 1984 Yamaha YTM225DX and it's not charging the battery. Taking the easy way out, I swapped the regulator/rectifier and OF COURSE that didn't help at all, at least now I've got a spare one. Today I ohmed out the the 'source coil' and got 514 ohms of resistance from the Brown Wire (which goes to the source coil) and ground.
Does that seem high? Anyone know what a good source coil will ohm out at? Thanks for any help.

[Doc Holliday]

Anyone want to just unplug the harness on their 225DX on the left side of the engine and take an ohm reading from the brown wire (on the 4-wire plug that goes into the engine just behind the pull start) to ground? If so, thanks in advance for helping me out.

[Howdy]

If you have the shop manual they should have the way to test the stator in there. I have the clymers manual at the shop, but I am at home and won't be out there for a few days.
Howdy

[barnett468]

Okay...got a 1984 Yamaha YTM225DX and it's not charging the battery. Taking the easy way out, I swapped the regulator/rectifier and OF COURSE that didn't help at all, at least now I've got a spare one. Today I ohmed out the the 'source coil' and got 514 ohms of resistance from the Brown Wire (which goes to the source coil) and ground.
Does that seem high? Anyone know what a good source coil will ohm out at? Thanks for any help.

Hello Doc


Since Howdy is ot I thought I would post this info for you so you could have it right away.

Coils should be around 68 degrees, set meter on R X 10.


Pick up coil resistance between white/red and white/green wires is 196 ohms + - 10% so around 176-116 ohms.

Source coil also called the charging coil is 381 + - 10 % between brown and black wire.

I would think that because yours is 514 it is good since it is a coil only even though it is high. They really should never change from new. They should either work or not as far as I know but others might know better.


PG 188 [UPSIDE DOWN] AND 200

http://www.oscarmayer.net/atc/manual...225-fm200l.pdf


Ricky Stator, source coil $39.95

http://www.rickystator.com/catalog/y...page=4&sort=2a


Hope this info helps.

[Doc Holliday]

Thanks for posting!

I got 199 ohms from the pickup coil so that's right on. While running, I was reading only 11 volts at the battery terminals so I know it's not getting charged...I did swap out the regulator but I'm unsure if the second one was good or not. More testing tomorrow. Thanks again.

[barnett468]

Thanks for posting!

I got 199 ohms from the pickup coil so that's right on. While running, I was reading only 11 volts at the battery terminals so I know it's not getting charged...I did swap out the regulator but I'm unsure if the second one was good or not. More testing tomorrow. Thanks again.

Hello Doc


I am an electrical hack but a half decent hack. I'm 99.9 percent certain you can simply push a safety pin into the brown wire while it is running and read the volts. If it is over 12 v it is good. The wiring diagram shows only one wire coming from the source/charging coil so I am assuming the black is grounded inside the stator. Is this correct? If so just ohm from brown to ground, but you probably already know that?


Hope this info helps.

[Doc Holliday]

Hello Doc


I am an electrical hack but a half decent hack. I'm 99.9 percent certain you can simply push a safety pin into the brown wire while it is running and read the volts. If it is over 12 v it is good. The wiring diagram shows only one wire coming from the source/charging coil so I am assuming the black is grounded inside the stator. Is this correct? If so just ohm from brown to ground, but you probably already know that?


Hope this info helps.

Correct, the black grounds to the stator body. This is what I've figured out so far - I think - When you test from brown to ground, you are testing the charging coil resistance. The white/blue and white/red wires are for the pickup coil which tests at 199 ohms. The two loose wires outside the harness (one yellow and one white) are for the two different windings of the lighting coil. The yellow tests at 1 ohm and the white tests at 4 ohms resistance to ground. Not sure if those are good readings or not but that's what I've got.

[barnett468]

HELLO


All that info is on pages 198 thru 204 in the manual below that I posted in my previous link for you. Did you not see it? Just click on the blue line and wait up to 30 minutes.


PG 188 [UPSIDE DOWN] AND 200

http://www.oscarmayer.net/atc/manual...225-fm200l.pdf

[Doc Holliday]

30 minutes to load? I'll try it later, but thanks for the info! I will have to take a good look.

Edited to add: GOT IT. It looks like I'm way over on the acceptable ohm range for the Charge Coil. Got one coming, may as well change it while it's apart and then I'll see if that does it.

Thanks.

[Keldog]

Hey Doc, When you put the new charge coil in did that fix your weak spark issue? I've currently got a reading of 60k ohms on my charge coil with no spark. Hope your able to remember 9 years later lol

[ATC200X4716]

A 60k coil should be changed, for all intensive purposes that's an open circuit. Make sure you are getting a good connection with the meter and a good ground.