How long did this bike sit up before you took it off his hands? .... I would definitely keep trying with a good fuel system cleaner like seafoam ...
You have air, you say you have fuel, and you say the spark is there .... well something somewhere is not as it should be ... try swapping the injector connectors back ... check your static timing to make sure the timing is not off and to see if the cam sensor is still working right like it should ...