99 yz 125 no spark


22 replies to this topic
  • yz125_99

Posted July 18, 2013 - 12:18 PM

#1

Hello, I am new to this forum and would like to try to figure out what is wrong with my (semi) newly acquired bike. I bought the bike about 2 months ago and up to now it has run perfect, about two weeks ago though it started acting up. I had just gotten home from a weeks vacation and wanted to go riding but the bike wouldn't start, I thought this was very odd as i had just ridden it the week prior to when I had been gone. I got a new plug for it figuring that it was just flooded, stuck it in and still wouldn't go. That is when i decided to check for spark, and sure enough there wasn't any. I have already checked the grounds and cleaned out the cap connection, as well as ruling out a bad kill switch. Now I am quite confused as to what would be causing this? Is there a way to test the coil? I am pretty handy so I would like to try to fix this myself if i can! Any help would be greatly appreciated!!

  • Mx Factory USA

Posted July 18, 2013 - 04:49 PM

#2

First pull the cap off the coil and cut the wire back a half inch, screw the plug back on the wire and give it a go. If still no spark get yourself a manual and multimeter. Check resistance on the coil and stator. If those check out fine replace CDI.

  • yz125_99

Posted July 18, 2013 - 06:07 PM

#3

First pull the cap off the coil and cut the wire back a half inch, screw the plug back on the wire and give it a go. If still no spark get yourself a manual and multimeter. Check resistance on the coil and stator. If those check out fine replace CDI.


Will do! Thanks!

  • yz125_99

Posted July 20, 2013 - 07:48 PM

#4

So I finally got out to the garage again today and cut the cap back. I am not sure if I tested the coil with the right procedure though, I took put one point in the cap and one on the coil where the wire connects, I didn't get a reading though? I just find it weird that the bike just suddenly won't start?

  • 1fastbadA

Posted July 20, 2013 - 08:06 PM

#5

  • service manual use it religiously


  • yz125_99

Posted July 20, 2013 - 08:45 PM

#6

  • service manual use it religiously


I was able to find the reading numbers by doing a Google search, I was hoping someone knew the procedure for testing the coil/stator.

  • Likemike_Lilshawn

Posted July 21, 2013 - 12:25 AM

#7

I'll trade mi bike for your yz

  • Polar_Bus

Posted July 21, 2013 - 03:31 AM

#8

So I finally got out to the garage again today and cut the cap back. I am not sure if I tested the coil with the right procedure though, I took put one point in the cap and one on the coil where the wire connects, I didn't get a reading though? I just find it weird that the bike just suddenly won't start?


Not sure what you mean when you say "I didn't get a reading" ? Are you using a ohm meter ? Do you have the ohm meter set to the correct scale ? (should be "1", but some digital meters are self sensing) Might be a good idea to take the coil to your local Yammi dealer and the service dept can check it for you.

  • yz125_99

Posted July 21, 2013 - 05:10 AM

#9

Not sure what you mean when you say "I didn't get a reading" ? Are you using a ohm meter ? Do you have the ohm meter set to the correct scale ? (should be "1", but some digital meters are self sensing) Might be a good idea to take the coil to your local Yammi dealer and the service dept can check it for you.


Yes I have the right meter and it was set to 1, maybe that is what I will wind up doing although I would like to rule out the stator too if I can.

  • Fast_Eddie

Posted July 21, 2013 - 05:30 AM

#10

replace the spark plug cap with an NGK. It's worth the $8.00 just to rule it out. Some YZ's it that era had fussy caps.

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  • yz125_99

Posted July 21, 2013 - 09:11 AM

#11

replace the spark plug cap with an NGK. It's worth the $8.00 just to rule it out. Some YZ's it that era had fussy caps.


Would I have to order that online or could I get it from a parts store?

  • yz125_99

Posted July 22, 2013 - 12:54 PM

#12

So I got my coil trested at my local dealer today and it is not the problem, I also picked up a cap on the way home. Put it back together and still no spark! Stator?

  • Fast_Eddie

Posted July 22, 2013 - 03:37 PM

#13

If you have disconnected the kill switch and ruled out wiring then you're only left with Stator and CDI. I've never heard of anybody needing a CDI on a YZ. I have burned out a couple stators over the years on other bikes. If you did need a CDI that might be available from dirtbike junkyard that is always parting stuff on Ebay.

  • yz125_99

Posted July 22, 2013 - 03:45 PM

#14

If you have disconnected the kill switch and ruled out wiring then you're only left with Stator and CDI. I've never heard of anybody needing a CDI on a YZ. I have burned out a couple stators over the years on other bikes. If you did need a CDI that might be available from dirtbike junkyard that is always parting stuff on Ebay.


Is there any way to test a stator?

  • Mx Factory USA

Posted July 22, 2013 - 09:04 PM

#15

Is there any way to test a stator?


Pick up coil res use + test lead on white/red lead and - test lead on white/blue lead for 248-372 ohms (100 ohm scale)

Source coil 1 res use + test lead on black/red lead and - test lead on green/white lead for 720-1080 ohm (100 ohm scale)

Source 2 coil res use + test lead on green/blue lead and - test lead on black lead for 44-66 ohm (10 ohm scale)

  • yz125_99

Posted July 23, 2013 - 07:54 AM

#16

Pick up coil res use + test lead on white/red lead and - test lead on white/blue lead for 248-372 ohms (100 ohm scale)

Source coil 1 res use + test lead on black/red lead and - test lead on green/white lead for 720-1080 ohm (100 ohm scale)

Source 2 coil res use + test lead on green/blue lead and - test lead on black lead for 44-66 ohm (10 ohm scale)


Thanks! That is exactly what I was looking for!

  • yz125_99

Posted August 05, 2013 - 02:22 PM

#17

So I found out my stator was bad, I purchased a brand new one off of EBay for a great price and got the bike running. I also found out from my dealer that it is actually a 98 instead of a 99. Now I have a new problem, the bike idles slower than before and it seems to run different, more "pops" and crackles in the exhaust note. I took it out for a test ride and right away it just started bogging after I got to 1/2-3/4 throttle! Only other thing I did was clean the air filter and re-install...any ideas?

  • Fast_Eddie

Posted August 06, 2013 - 06:32 AM

#18

Rebuild the carb and clean out all passages, then remove the upper power-valve cover and spray it out with brake cleaner or WD40 if goo is holding it closed.



  • yz125_99

Posted August 16, 2013 - 04:09 PM

#19

Any tips with timing? I did read the "250 timing thread" and got some good tips but the timing marks looked different than on my 125. Any help would be greatly appreciated!

  • Mx Factory USA

Posted August 18, 2013 - 09:20 AM

#20

Any tips with timing? I did read the "250 timing thread" and got some good tips but the timing marks looked different than on my 125. Any help would be greatly appreciated!

 

This thread will help you 

 

http://www.thumperta...gnition-timing/







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