Check your coils, air leak or HT leads. It won't be crank sensor. That leads to no start conditions. If you haven't adjusted the valves most recently then it can't be a tight exhaust valve. Your valves loosen over time with mileage.

1200CC BIG BORE, W/WISECO PISTONS,.250 STROKED CRANK, PORTED/POLISHED HEADS AND LARGER VALVES, CUSTOM WELDED EXHUAST, DUAL 42MM MIKUNI CARBS.