Author Topic: YZ125G stator winding resistance.  (Read 1044 times)

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Offline baitfish

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YZ125G stator winding resistance.
« on: June 26, 2018, 02:39:17 PM »
Hi Lads,

I'm slowly piecing together my YZ125g project and i've run into a bit of trouble with the stator set up.
I've checked the resistance on both of the coils, one was reading 279 ohms the other 1389 ohms. The
clymer manual ive been using states that the values should be 470 plus or minus 10% and 1470 ohms
plus or minus 10%.

So ive been on the hunt for some replacements and brought a second hand set, that again tested at roughly
the same values. So i figured i had another out of spec "coil 2" and bit the bullet and purchased a NOS
"coil 2" to suit the G. when i checked its resistance it came up with 280 ohms as well.....

So i've done a lot of snooping about and i haven't been able to find a straight answer, does anyone know what the
correct ohm readings should be please?

I did find the following information on this forum and it backs up what readings i have been getting, but some extra clarification
would be greatly appreciated.

Hate to disagree Rusty.
Red to white should be 500 ohms +/- 10%

These are for yz125g and later.
stator readings are
red to white red 270 ohms
brown to red 1437 ohms
10%  variance either way

these are standard readings for nearly all yz125s

The ignition system for the yz125f is actually from the yz80f


Cheers!

Offline alexbrown64

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Re: YZ125G stator winding resistance.
« Reply #1 on: June 26, 2018, 06:12:38 PM »
Hi Baitfish.. you should put some pics up of how everything is going.
My G project has stalled a whisker due to so many other projects.. but i still have big plans for her.

I have a brand new Yamaha YZ125G factory workshop manual printed in 1980.
Here is the page on the electrical specifications as described by Yamaha. Hope this helps,
Cheers,




Offline baitfish

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Re: YZ125G stator winding resistance.
« Reply #2 on: June 26, 2018, 08:05:37 PM »
Hi alexbrown

Thanks for the reply, it has me in a pickle but! I've got 3 high speed coils that all read around 280 ohms, including a NOS item. I'll dig it out tomorrow to get the part number off it.

I'll try to get some photos together, I've got a random collection on my phone from different stages. Who is everyone using to host photos now photo bucket has gone to poo?

Offline tony27

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Re: YZ125G stator winding resistance.
« Reply #3 on: June 27, 2018, 08:00:56 AM »
Think a few people are using imgur now, may have the spelling wrong

Offline baitfish

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Re: YZ125G stator winding resistance.
« Reply #4 on: June 27, 2018, 08:38:22 AM »
Thanks tony27. i think i've worked out the photos.

This is the NOS item i got from the states and it measures 293 ohms, the insulation resistance is above 200 megohms
so it seems the insulation has not broken down either. I've used my digital fluke meter and my kyoritsu analouge just
to double check. very strange indeed.




you can see in the photo that there is no signs of resin or solder on the tails of the winding leading me to believe it really is a
NOS item.

Offline baitfish

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Re: YZ125G stator winding resistance.
« Reply #5 on: July 17, 2018, 09:30:18 AM »
So a bit of an update, I've had been able to get someone to test a coil on a running YZ125H, as far as i can tell by part numbers and the
manuals, the G and H use the same coils.

The running engine measured at roughly 280 ohms,

The second hand coil I brought, that supposedly came from a running bike when wrecked, tested at roughly 280 ohms,

The NOS item I got from the states, still in its packaging, measured at roughly 280 ohms,

The coil that came with the bike measured at roughly 280 ohms

So from this i'm thinking that the G and H both run 270 ohms high speed coils + or - 10%, not 470 ohms like the manual states???????

I put my stator back together, mounted it in the bike and gave it a few test kicks with the plug out. Looks to be a nice strong blue spark.

So hopefully that is that and i can continue on with the build. That was a few hundred dollars and few months of running around chasing information
and parts for no reason it seems.

Offline Woody

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Re: YZ125G stator winding resistance.
« Reply #6 on: July 17, 2018, 08:04:59 PM »
The Technical Bulletin confirms your reading at 270ohms. Must be a misprint in the manual.



This site inspired me to do mine.

https://projectyz.wordpress.com
WANTED 

1988/89 125 - CR KX YZ   
YZ125G, YZ250H and YZ80G parts
IT200 stuff
CR250RD parts

Offline alexbrown64

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Re: YZ125G stator winding resistance.
« Reply #7 on: July 17, 2018, 11:04:06 PM »
Funny how you can get focused on one thing... Good to see some alternate documentation that confirms the different reading to the manual.
As for the projectyz.. it also convinced me to start on mine. 
Hope to kickstart my 12G project again soon..

Cheers,


Offline baitfish

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Re: YZ125G stator winding resistance.
« Reply #8 on: August 08, 2018, 08:10:25 PM »
Hi Woody,

thanks for confirming that with the bulletin, it still blows me out that three different manuals i had access to all had the wrong values.

cheers

Offline fred99999au

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Re: YZ125G stator winding resistance.
« Reply #9 on: August 11, 2018, 05:56:35 PM »
In my experience, the clymer manual makes an excellent resource to put under the bike if there is an oil leak as the paper is quite absorbent. I dont think it gets better from there as if it is the one I have it covers about 95 bikes over 15 years.