I can't start the engine.

[Maciek]

Sometimes my ZR1 won't start the engine. I don't know what else I can do, because I changed: started motor (twice, and I mount heatshield), battery (twice), lock ignition with key (twice), clutch pedal sensor (once) and nothig helped. I turn on ignition, I want start the engine and ....nothing. It always happend when I'm hurry. :(
Thanks for any helped reply.