1998 OX66 won't crank

[duckdowner]

I have a 1998 OX66 that has give me nothing but problems this summer. I have replaced all the fuel pumps, had the injectors sent off and cleaned. After fixing each little problem along the way the engine runs great for about 50 or so miles and then i get a new symptom. Right now i cant get the engine to crank. I checked the O2 sensor according to the manual and it checked good. Is it possible that my CDI is bad and how do I know for sure?

[99yam40]

Test/check the inputs to the CDI and the out puts from the CDI according to the manual using the proper test equipment as explained in the Yamaha service manual for your motor