I purchased a 2001 big bear 400 with no spark after multiple test I have came to the conclusion that the cdi box is bad and I need to replace it. My question is it shows that there are not any compatibility cdi other than a new 1 made for this bike and I can't see spending 400$ just on a cdi box if I can use 1 off another bike. I have looked and the kodiak has the same plug and very similar wiring diagram has anyone used a different cdi box on a big bear similar to mine

 

You will be lucky if a different box will fit. Yamaha put lots of circuits with little or nothing to do with ignition, through the CDI. They also made different CDIs for each model and often year. I suspect this was to discourage aftermarket makers from bothering to copy them. You could take the exciter coil and trigger coil wires and feed them through a cheap Chinese Kids Quad CDI, to get a spark. Advance curve may not be quite right and what this would do to all those other circuits going through the Yam CDI, is anyone's guess. I got a Honda 450 in with no spark and found someone had done this mod, it had run for a while on a Chinese Kids Quad DC CDI but, as it had failed, I converted it back to standard wiring and fitted an aftermarket Honda 450 CDI to it.

 

did you have any luck figuring this out?