To get the cheat screen you press R1 at the Select Event menu.

N0CR4SH No crashes
H34DL3SS Headless rider in practice mode
BL0CKM3 All riders block you
G14NTS Giant riders
N00FFTR4CK Cancel Off Track reset
B1GSPR4Y Big dirt sprays
M0R3C4MS Additional views
H0P Extra hop button
SK1PP1NG0K Cancel Skipping Track reset
B1GB1K3S Big bikes
N0R1D3RS No riders
M00N Moon gravity
S4TVRN Saturn gravity
V3NVS Venus gravity
M4RS Mars gravity
VR4NVS Uranus gravity
N3PTVN3 Neptune gravity
M3RCVRY Mercury gravity
JVP1T3R Jupiter gravity
PLVT0 Pluto gravity