XR600, no spark,HELP!

[anca]

I have a XR 600 ’93 which during returning home from riding has suddenly stopped. I have no spark! I checked out everything with a ohm meter, the contacts, the pulse generator, the alternator, the engine stop switch, the cable continuity, the coil, the spark plug. Everything is by the book (I have the service book). It remains only the CDI. Is there any possibility to check the CDI? I have a CDI from a XL500 ’83, the electrical connections are almost the same, can I swap the CDI without the danger of damaging the XL CDI? What else can I do (I have no access to another XR CDI)?
Thank you in front for your answers!

 

[GREENBEAN]

I had an XL600R and the ground wire from/to the coil corroded. First the bike started cutting off at full throttle I couldnt figure what was wrong till I noticed a big arc coming from under the gas tank every time I cracked the throttle wide open. Scary! make sure all those connections under the tank are good, clean and not corroded.