It has a few versions but the exact version I’m looking for sounds like this YouTube – Sasuke 23 Intro Theme (http://www.youtube.com/watch?v=W2aX4avOAYU) (Heres the longest version of that I can find SasukeSongSample.mp3 (http://www.mediafire.com/download.php?1dsij6vci5d6v5p) ) (Also Sasuke never uses their own music)
Also a close version has been heard of 6:26 (But the link should skip) of YouTube – OOO ep 2 part 2 (http://www.youtube.com/watch?v=ewM3eKgNzWU&t=6m29s) (It doesn’t come from Kamen Rider though)
If it helps you guys find the song a close version has been heard in YouTube – (http://www.youtube.com/watch?v=GHj_bSeRdnM) (it doesn’t come from that franchise, I checked that too)