The mtxisland.rar file you have requested: Map Mods / MotoCross Track Island - 721.04kb is not available. Perhaps try browsing all files for the game Grand Theft Auto: San Andreas and upload any files you want to share or are missing. This is the only information we could locate:
Here is a map modification that will add an Island to GTA San Andreas. This island includes A motocross track, 16 weapons, 9 vehicles, A complete gym, A casino and several other things.