84 Suzuki lt125 CDI Box bad

[RepairmanJake86]

Got an old 84 suzuki lt125 that isn't getting spark. Coil and pickup coil ohmed good, CDI box ohm readings were bad. All I can find are used CDI Boxes for 100 bucks or more for this model...what the hell?  Why and is there any other options out there? Thanks

[MarkinAR]

You can't test a CDI with a multimeter, you need a full CDI test bench for that.  If you have ruled out all other reasons for no spark, then it's probably the CDI.  Sometimes you can bake them in the oven for 5 minutes at 200 and try and sometimes they'll work for a few minutes.  $100 for a good used OEM CDI isn't bad unless you're comparing them to $30 chinese junk.

[RepairmanJake86]

Appreciate the reply. I went by this troubleshooting guide. I'll attach a pic of it.

[MarkinAR]

Interesting, thanks for posting.  I've never seen a manuf suggest testing a CDI by ohm load.  All of the Honda stuff you can't get a value if the CDI isn't activated so there are no good tests for them.  I guess if yours doesn't fall within spec as posted by Suzuki, then I guess we have to assume it is indeed bad.

[RepairmanJake86]

For sure brother. I thought it was odd too but I did have 2 ohm readings perfectly within specs so I guess it's a legit test. CDI is definitely bad. I found a used one with a guarantee for 65 bucks. I guess that's the way to go.

[Savage]

Markin has made a legitimate point, resistance testing is NOT 100 percent accurate test for a CDI for several reasons. Have you tried disconnecting the wire going to kill switch before replacing CDI?

Have you tested for continuity between ground pin and the other pins?

Edited January 23, 2022 by Savage
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[RepairmanJake86]

On 1/23/2022 at 11:41 AM, Savage said:

Markin has made a legitimate point, resistance testing is NOT 100 percent accurate test for a CDI for several reasons. Have you tried disconnecting the wire going to kill switch before replacing CDI?

Have you tested for continuity between ground pin and the other 

Yes and yes....UPDATE: I got the used CDI Box in yesterday and ohmed it out and u guys are correct. Ohmed pretty close to the bad one. That being said, the diagnosis being the bad box was correct because I got spark and she eventually fired up. So that's good news. I appreciate your guy's responses and help!

[Savage]

Excellent! Glad ya got it running!