EX500 cuts out randomly
 

Bike runs awesome but sometimes youll be riding and the rpms drop to zero form like 3k. It does this for like 15 to 20 seconds seconds then goes back to normal and works fine. Its really annoying cause sometimes it does this and sometimes not. I replaced the IC Igniter with a used one because mine wouldnt work unless you tapped on it. My bike never did this until i replaced the igniter. I wonder if its bad or should i change the pick up coils also? What do the pick up coils do? Would a stator cause this? carbs are clean and adjusted

Thanks