I was working on my friends bike last week, he's using a gen2 bottom end with gen1 block and head in his 05 busa, but he couldn't get it started, so i told him we have to change out the rotor because the gen2 is a 24-2 and the gen1 is a 24-1, so we put the gen1 rotor in and try to install the stator it would not fit it was too big, so we had to use the gen1 stator as well.