Suzuki ATV Forum banner

Lt125 Fried CDI Box??

1013 Views 10 Replies 4 Participants Last post by  tomdevon60
I made a post a couple weeks ago about my 84’ lt125 being hard to start when cold. Turns out it wasnt getting spark, or at least not all the time? I looked closer at the CDI unit and this doesn’t look good 👀 has anyone else experienced this??? This morning it wouldnt start (no spark) I played with some connections, got it to start. And now it wont start again im kinda going crazy with this little thing any help is much appreciated. I took the left side pulley off just before and noticed the rotor or flywheel had some whitening around it im not sure what that is. Im stumped yet again


See less See more
1 - 11 of 11 Posts
Holy Cow. A hair under 40 years old and that thing looks like it was just driven off the showroom floor. If that is a CDI box, it's the strangest looking one I've ever seen. I think you're on the right track though. Gotta be an electrical issue cause mechanically, that machine looks perfect.

You say you couldnt get any spark, but after playing with some wires, you got it to start. I'd go with that to begin with. What did you do or move that allowed you to get spark when there was none before?

How about spraying everything down with electric contact cleaner. Try the easy stuff before getting to the more complicated. Electric issues are so not my bag so hopefully some others around here can help you troubleshoot.
  • Like
Reactions: 1
Thanks its a clean one. I did get a new seat cover upholstered and some reproduction graphics but other than that its oem. That CDI box is suspect, looks like someone superglued pepples onto it. I looked up used ones on ebay and they do not look like that lol

Same, electrical is my worst skillset when it comes to atvs/bikes. But all I messed with to get the spark was the black/red wire connection, blue wire connection, and red/yellow connection which is the pickup coil I believe. I pulled the ignition coil ground wire off too, I sprayed them all with contact cleaner.

After it ran I put all the plastics back on, stored it in the garage, thinking it was all good. Came back out an hour or two later to verify it was fixed and badabing no spark. Pulled it 20+ times and nothing. When it runs it purs like new as it should with just over 300 miles.

Tomorrow I will mess with the wires one by one and try to start it after each one, and see if I can dial in the issue. What a PITA, I have a multi meter but don’t really know how to use it.
See less See more
Hello I just picked up a 85 Lt 125 and someone went through and changed the wiring All up and have no spark pull off the pull starter took off the magneto need it cleaned but I don't know what's wires what and what goes to the CDI it sounds like you're trouble might be the coil you get a high and a low spark you're probably getting a low spark tried clearing your spark plug boot And can anyone put a picture up of the wiring from your magneto to your CDI
If I spray starting fluid in my airbox itll start 1-2 pulls. So I dont think it was either the cdi or ignition in the first place. Ill post a pic of thaf tm
If I spray starting fluid in my airbox itll start 1-2 pulls. So I dont think it was either the cdi or ignition in the first place. Ill post a pic of thaf tm
Hello Frank, Tom here I recently joined this group looking for LT 125 electrical parts . I was reading some of your posts and it sounds like you were chasing the same problems I have . In your post you mentioned that you replaced some parts like the stator AC coil and the ignition coil but later discovered it did not help . My question to you is would you be interested in selling any of your removed and replaced parts that you believe are still ok ? I have been trying many parts sources but have not been able to find any and apparently they are discontinued. Any help or even your parts source would be greatly appreciated. I'm not sure where you are located in the USA but I'm near the US & CAN border at Sault Saint Marie ONT. CANADA .
Hey Tom. Since I posted this I bought a used cdi box on ebay and still had the same issues with hard starting when cold. I only have this fried looking cbi box that I would sell, I haven’t tested it. The quad has been sold
Thanks for responding Frank. I suspect my stator AC coil is my nemesis as I get weird reading on the multimeter when I try a continuity check look for a break in the coil wire. I was wondering where you were finding parts for your LT 125?
I got my used cdi box on ebay
1 - 11 of 11 Posts