Before The Shadows Fade
This is from "Futago no Pupurin Vs. Purin! Utau Pokémon Konsaato" AND "Utatte! Purin!" In "Futago no Pupurin Vs. Purin! Utau Pokémon Konsaato" Musashi and Kojirou's names are flipped so I wrote it up that way since "Futago no Pupurin Vs. Purin! Utau Pokémon Konsaato" is in season five and "Utatte! Purin!" is in season one. The "oo"+"yeah" are from "Futago no Pupurin Vs. Purin! Utau Pokémon Konsaato" only and the first line of the song is from "Utatte! Purin!" only.

[James:] Pump it to the max.
[Jessie & James:] You know it's us Team Rocket and we fight for what is wrong.
We're tired of our motto so we thought we'd try a song.
[James:] James.
[Jessie:] "Jessie!"
[Jessie & James:] The speed of light.
Prepare to fight.
[Meowth:] Meowth, dat's right.
[James:] I am the handsome one.
[Jessie:] I'm the gorgeous one.
[Jessie & James:] Looking good is lots of fun.
We get some things wrong but we keep rolling along.
[Jessie, James, & Meowth:] We want to capture Pikachu-we hope to do it soon.
And when we do we'll be the new stars of this...
Cartoon.
[Jessie:] Oo!
[James:] Yeah!