I have a 1987 FJ1200
when I tried to put it in gear, it immediately died.
This should be a good indicator if it is a mechanical clutch issue or a switch issue as Chris mentioned.
When you pulled the clutch lever in and the bike immediately died...... This could be a Clutch switch, side stand switch problem.... Did you recently change the oil and possibly pinched the side stand switch wire in the oil filter cover?
When you pulled the clutch lever in and engaged 1st gear....Did the bike lurch forward violently? This would be an indication of a mechanical clutch failure, Slave cylinder failure or master cylinder failure.
Fred