Re: 1995 cbr900rr starts when tilted?
There is safety cut off switch for the kickstand. Does the side-stand light on the dash come on when bike is upright and having this issue? Does your side stand-light work at all?
Check to see if starter is getting voltage when bike is upright, if so, faulty starter.
I would check starter button, ignition switch, kill switch, then wiring.
But since this happens after a "long ride", I would assume heat and expansion is involved. So I would suspect starter and side stand switch first. Buy a cheap multimeter and learn to check for voltage, very easy to do.
Can also very easily be loose wiring.