You get points for persistence. So new plugs now and there was a real change from previous attempts. My old vw injection systems had an injector dedicated to spraying an initial charge upstream at the air box to facilitate initial firing. Have you tried ether starting fluid to rule out fuel delivery? If it does not fire with that sprayed into the intake then it has to be spark or spark timing. Only thing after that is compression. The other thing my vw system was sensitive to was the cylinder head temp sensor. If the sensor was bad the ecu thought the engine was hot and would not trigger the cold start injector sufficiently and air bypass valve to bump the idle. No start. Even if the sensor was good and it was not screwed into the head solidly and grounded engine would not start. Could the fuel be contaminated? Put some water remover in the tank and add more fuel and agitate the tank. Man what mystery. Before you put the new battery in did you try to jump the bike with cables and a car battery or something like that? That's all the crazy ideas I have except for new plug wires or confirming continuity and solid connections with the current ones.