Hi everyone, my name is Jason and I'm just beginning to dabble in SW. I have a question that I've been pulling hair for that past few hours. Before I go bald I am seeking help.

I'm trying to model a motorcycle triple clamp. The top surface is a curvatured profile, as is the bottom surface. I've sketched a profile using a 'cross' plane to get this profile.

You can see the profile created, I marked with a red line here:

The problem that I can't seem to figure out is I'm trying to extrude the top surface lower, but matching the same profile. So far I've created a surface that is flat (indicated by my blue line in the picture above).

Below is a picture of a model that I'm trying to achieve, which is created by a professional. Notice the profile line that I've drawn in purple, it is curved. This is the curved surface that I'm trying to achieved, but if I create a sketch using a plan and extrude it straight down, it is flat.

So how do I create a sketch so that I can extrude down, yet the surface is curved and not flat? Any help is appreciated.