904 is plenty of torque for two up riding, I barely got mine broke in before I went to Sturgis. I am about 220 myself, my girl and baggage put the load at about 400. I made some starts in second gear (accidentally) a few times from dead stops, and the mountains were no problem even when I was geared too high it pulled through without bogging down. Runs great as a solo, can keep up with almost anything now, and out run way more than before. I also did head work to mine, but for a start, the bore kit would be fine for more power.
