First of all, the mission doesn't have anything to do with bikes. Its called like it due to my lack of creativity.

A chinese agency and non specified agency are exchanging very valuable information with a rival agency. Toreno wants you to get some weapons and take a plane from the airstrip and head to Mount Chilliad. Once there you'll meet 2 rookie agents (that doesn't have to survive, they knew what they sign into.) Go to 2 different points in Chilliad, kill the agency leaders and get the info. BUT HURRY UP!!! Toreno is meeting the "Big Man" in the local mini-market (24-7) in 12 hours (game time.) Hurry!!