Instructions
Navigate to Mount Chilad. Mount Chilad is the highest peak in "Grand Theft Auto: San Andreas" and can be seen from most other locations in the game. It is located in the town of Whetstone.
Climb to the top of Mount Chilad. Arrive at the top of the mountain between 7 a.m. and 6 p.m.; between these times is when the races occur.
Find the mountain bike at the top of Mount Chilad. Now you'll be able to participate in The Chilad Challenge mission. During each of the three individual races, you earn a small amount of cash for completing each race successfully.