Conversation so far:
Where was Nelson Piquet born?
Nelson Piquet was born in Rio de Janeiro, which at the time was the capital of Brazil
Was Nelson Piquet interested in racing or races as a child?
Nelson Piquet started kart racing at the age of 14
Did Nelson Piquet race with friends or was there a race for kids?
Nelson Piquet and three friends brought a 20 hp cart and participated in Brazilian go-karting

Question: What did he do after the 1972 and 1972 national championship?
Self-contained rewrite: What did Nelson Piquet do after the 1971 and 1972 national go-kart championship?