CDI Repair?

This is just an inquiry thread.

I know there are references to CDI repair but I was wondering how many of you have attempted it. Does anyone know what goes wrong with them besides loose solder joints? Has anyone successfully repaired one that they thought was faulty?

 

I have not but I would be curious to see what you find.

For reference here is the best information, on the internal workings, that I have found to date:



http://users.rcn.com/kochc/moto/spark/ig_repair.html

In addition, a good VFRworld thread on this topic:

http://vfrworld.com/forums/mechanics-garage/6473-my-vf1000-frustrations-4.html#post295639

Good luck and let us know how you make out.

 

I have done an unsuccessful attempt to repair a friends VF400 CDI back on the productive days of 90something.
Symptom was the bike was not revving smoothly. Like having an additional rev limiter; when bike was cold it was working ok up to 6~7K but a couple of minutes later the limit was down to 4K and continuously fluctuating. I changed the transistor but I had no success and gave up as the daughter board clearly seen seen on picture above was covered in my case with an aluminum shield and filled with resin.
The CDI was replaced and bike was fine afterwards.

Jumping into conclusion I would say there are chances of repair of daughter board as it seems all analog; but then again there might be a bottom layer filled with more components.

 

Looks like electrolytic cans on the left side, on tube electronics or power supplies, those are usually suspect in failures.
I see a diode symbol in the middle, that might be worth checking, you could also check the resistors and the transistor there.

 

I was reading in the other thread VF1000 Frustrations and I am curious. I read somewhere else that the boxes are interchangeable. If the rev limiter is in the larger box and the CDI units are interchangeable could you run two of the smaller units and eliminate the Rev limiter? The tach wouldn't work but... Thoughts?

 

CDIs are commonly repaired on VTR 250s: usually just one inexpensive component.

http://www.vtr250.com/cgi-bin/yabb2/YaBB.pl?num=1104268518

 

I don't recall the VF400 CDI I opened having a varistor but I might be wrong.
In any case what works for one might not work for another and the repair mentioned was for the problem "CDI dead".

I had once modified a CDI of a RG500 according to schematics my friend had download from internet and box was full discrete "through hole" components, so I am convinced this specific CDI can be repaired in everything but a custom made IC.

 

Yeah, I can't tell if that board on the bottom has an IC attached to the underside or not.