To go from Lima do Sao Paulo is relatively simple. You can travel south from Lima until you reach Ica and then go to Cuzco, Porto Velho, Cuiaba, Rio Verde, Uberlandia, Ribeirao Preto and finaly Sao Paulo using the new Interoceanic Highway
If you want to go north and ride through Colombia and Equador a a little more complicated as you said because is impossible to enter Brazil without going through Venezuela (because basically there is no roads connecting Colombia and Brazil). In this case you need to enter Brazil through Roraima, ride to Manaus, take a 6 days boat travel do Santarem and then ride south.
Going through Bolivia and Paraguay is simpler, you can enter in Brazil at Foz do Iguaçu and ride about 1000 kms to arrive in Sao Paulo.
Another option is riding from Lima to La Paz, Santa Cruz, Corumba, Campo Grande, Presidente Prudente and finally Sao Paulo.
If you have and doubts please let me know, and if you choose the first option let me know because I´m from Uberlandia and I can find you a place to stay, park your bike and buy you some
Suzuki GN125 2005
- Uberlândia / MG - Brazil
You don't need to have a big bike to have a great adventure.