about tyre pressure.
Why would you use tyre pressure above 40psi? Doesn't save that much fuel.
The recommended cold tyre pressure for different bikes is generally:
24-28psi for front(F)
28-32psi for rear with rider alone(R1)
32-40psi for rider and passenger(R2).
Even when tyres are hot it should not exceed 35psi(rear tyre) for a single rider.
GS150 manual recommends: 24(F), 28(R1), 40psi(R2).
I normally keep it at 28(F), 32(R1), because the tyres are not exactly cold when I reach the tyre shop. On longer trips (over 300km), I use 28(F), 35(R1), it saves a little bit of fuel but braking is slightly more difficult and it becomes a little bumpy while braking. At 40psi or more, it will be bumpy all the time.