2003 z1000 service advice

Hi Everyone. So my 'new' machine needs a service. According to the previous owner and the Owners book, the last service was 16k. It is around 21k now. It says in the book the next service is 20k.
What do I need to do? I can't find a list of the serviceable items anywhere, and it doesn't show it in the book.
What would be the best oil to use for these bikes?
Hoping to hear from other owners and what they do and products used.
Thanks in advance.
What do I need to do? I can't find a list of the serviceable items anywhere, and it doesn't show it in the book.
What would be the best oil to use for these bikes?
Hoping to hear from other owners and what they do and products used.
Thanks in advance.
