Resurrecting a dead CDI

We have all heard of a failed CDI unit of some sort in the past. Have you ever wondered why they fail? I hadn’t until I started work on the old NX650 I have for the scrapheap challenge.

What made me 100% sure that the CDI had issues was that the bike wouldn’t start unless you gave the CDI unit several hits with the handle of a screw driver and it would all of a sudden fire and the bike would run again but every time you wanted to start the bike you would have to repeat the hitting with the screwdriver.

I had no idea what demons lurked inside that mysterious little black box, until we cut mine open for a look see, we figured we had nothing to loose as it was no good anyway.

Once we cut the top out of it we were confronted with a rubbery material that needed to be peeled off, once it was peeled back it revealed a circuit board.

Upon inspection with a magnifying glass, it was revealed what was actually wrong with the CDI.

A lot of the solder joints on the CDI were cracked and had corrosion around them, which I think were only making contact after you hit the CDI.

I have a mate that is an electronics wizz, so I gave it to him to resolder for me as my soldering skills are limited to say the least.

He got busy straight away with the circuit board, firstly he had to unsolder the joints before resoldering them. The trick here, was to get the heat exactly right, otherwise the waterproof packing beneath the circuit board would bubble up through the board making a mess and causing the solder not to stick.

Anyhow after an hour of soldering Charlie had the unit resoldered completely.

We plugged it into the bike and it fired up straight away and revved freely. The test will be in the riding and to see if what we have done has affected the ignition curve and how it will stand up to the rigors of riding.

So there, CDI’s can be fixed with a bit of know how and patience. Here’s hoping I am not speaking to soon!