The only Europe to South America shipping details that we have are for Switzerland to Buenos Aires, and from London to Buenos Aires, all by sea, on the Shipping page. There is also a lot of info on the customs / paperwork process in Buenos Aires.
Expect the boat trip to take 4-8 weeks, and they usually cannot be more definite than that. NedLloyd (part of P&O has been recommended by travellers if you decide to ship by sea.
Depending on where you are going to be during that 4-6 weeks, it might be less costly overall to fly the bike with yourself (if you have to pay for hotel accommodation somewhere, for example).
With air cargo, it is usually simplest to go directly to the Air Cargo department of the airlines which fly between the two countries (usually the two national carriers).
Although you may find an agent can assist if there are specific paperwork requirements - this service is not free!
Good luck and let us know how it goes for you.
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