I know that this is a heavily covered topic, and just so you know, I did search before posting. I bought a 94 Tomos Sprint last week, and I am having a blast on it. My boyfriend got a nearly identical one though, and it seems like it has a little more pick up. The only difference between the two is some miles (about 2500) and the fact that mine doesn't have the airbox connected. They both have biturbos and bigger jets, but are otherwise stock. We both weigh about the same (within 10 pounds), so that wouldn't be a factor either.
His seems like it takes off a little faster, and mine will almost bog until it gets to about 5mph, then after it shifts into 2nd (at 20mph) it doesn't pull that hard until 25mph. I know it is pretty much stock and is not going to be a speed demon, but his will jump out in front and take off considerably faster. Mine seems like it might go a hair faster on flat land when the throttle is buried (at about 42/43mph on the speedo, whether that is correct is another story), but I would really rather have some more low-end due to driving in traffic.
The only thing it looks like it is missing is the boot between the mesh material on the carb & the airbox itself that is in the frame. I am hoping that the air filter is behind that mesh, but I haven't had a chance to look for it. Should I try running with the choke on for a minute to see if it needs more gas to balance it out? If that works- should I just upjet and not worry about it, or what? I am new to small engine performance and repair, so you will have to bear with me.