not sure how you would do it on an express but general wisdom on hopping a 2 stroke is increase the compression (top and bottom), rework the port timing, use a bigger carb and add a tuned exhaust. The japs are pretty good (excellent actually) of max tuning their stock shit right out of the box. however the japs also have a racing gene that puts ours to same. them little bastards will hop up and race ANYTHING! so, i wouldn't be suprised to find a japanese website that covers how to hop up an express.