thevo ...
Generally, repair is in the $100 range ...
Here is the link to the thread with pics, shematic, and parts list ... also Bosch test procedure and general circuit theory of operation for the Bosch BHKZ -- aka CDI unit!
Perma-tune CD or Bosch CD?
When the whistling stops ... it is usually the 2N3055 power transistor ... currently the most popular replacement transistor in the world ... $1 - $5 available from many, many electronic surplus and supply stores.