1985 Yamaha 80 Warm up CDI to make spark

[Freezeman]

I came across an odd temporary fix for a 1985 yamaha 80 ATV.  It has no spark, yet if I warm the CDI unit up a bit with a heat gun or hair dryer then it fires right up and runs fine until shut off then it returns to no spark until warmed up again. Partzilla shows $217 for a new CDI  

It's sort of nuts how I found out the fix to warm it up. My old shop TV requires my heat gun warm up around the transformer area every day before it will turn on too.  

[Frank Angerano]

The cdi is a sealed until.  And it’s that way for a reason.  It hates moisture!  Any moisture gets in and it’s dead.  I learned this a little while back while I was putzing around with my old cdi and went on YouTube to see what anyone has to say. One guy pointed me in the direction of putting the cdi in my oven. 

It worked believe it or not! 

Check this out. 

 

[Freezeman]

good tip. I will be trying that out with this one.

[Frank Angerano]

It truly was nuts to see this work.  I did it and the bike ran.  After a day it was not running.  Heated it up again and boom ran great.  So I added silicone and it was all good after that. I changed it anyway because I felt the possibility of moisture getting in could ruin a weekend of fun. But it’s a great trick to diagnose a damp cdi!