97 polaris explorer 500 won't start
 

ok i just bought this bike cheap the guy said the starter was bad i took it off and it was fine so i checked the gear it was ok. so i tried to start it and it was wirling the wrong way. si i reversed the polarity to get it to crank over and it did. well now i have no sparkn at the plug. ok so i used a test light and checked the cdi box nothing coil no fire there. ok so i got a wiring diagram and everything was hooked up right but still no spark. ok i am brain dead now any ideas. this bike shouldn't have a positive grond should it. help

97 polaris explorer 500 won't start
 

my bet, fried the cdi