Not tried that one.
MotoGP and TT Superbikes get a fair bit of use tho ( the latter bing the complete Isle of Man 37 mile circuit and well rendered -- can recognise all our pubs
)
But , YES, bikes ARE that hard to ride fast. A LOT harder than a car.
Are you running with separate brakes and moving the rider weight ?
If not, then the game AI may not be very good at getting those things right.
Use the rear brake only to point the bike if you're too fast and understeering -- GENTLY though or you'll "lowside". and NEVER touch the front brake in a corner !!
Get the rider to sit up and weight back on brake, weight forward on accelerating. Move the rider into the inside of the bike to increase cornering grip and speed.
You CANNOT slam the throttle on a bike coming out of a corner. It requires THE most delicate throttle control to JUST have the rear sliding fractionally. Any more and it will undoubtedly "highside" you !!
IN corner coming off the throttle and you will corner less, apply a little more throttle and you will get more steering ( to do with the way a bike squats under acceleration and alters the geometry )
Finally, ...... use the revs
To be REALLY fast you HAVE to use both analog sticks and make only the amount of movement necessary to be fast -- ie not slamming the sticks side to side/back/front etc. Build your speed up and lap times down.
SMOOTH is the way to speed on a bike on tarmac