It should be one of three things, the ignition switch, clutch safety switch or the solenoid/starter. Try to turn the key with a volt meter on the clutch safety switch. If it shows power when the key is placed to start, ignition switch is eliminated. Then put the volt meter on the solenoid/starter and see if there is any power with the key turned to the start position. Go from there. Curious to see if it might be the ignition switch.