I have an 01 scrambler 500 4x4. The only mods I have done to it is I had the restricter plug is drilled out and I have a jet kit. It runs great on flat land and through trailes. But if it bicycles (rides on two wheels) or when I jump it or if I cat walk it it starts to sputter immediately. It sat for a little over a year so I had the carb rebuilt then it quit running so I had it rebuilt again and had my fuel lines replaced because they where worn out inside And now I have a sputtering problem. Does anyone have any ideas? Thank you.