fuel guage probs

went for sunday ride out .guage had 4 bars on the guage .....98 miles later ,popped into garage for fuel and noticed the guage still had 4 full bars .........not happy as would like to see the fuel roughly left in tank .....rather than relying on mileage /top up ..
ANY THOUGHTS.......i did shake the bike about like a ravin loony ,to see if that helped ,it didnt so topped up the fuel and rode home ...

They all display slightly different, just safe average the tank on 165 miles max.

Could be the float switch that's sticking ?

hawk /s......gonna start lookin at 120 mark...
better safe  than sorry  ( a lesson learned )
mick ....will give next run out a good check ...will just keep rattling bike about and see what happens ....after that gonna let fuel run down a bit and remove the tank and force shake it ,nowt to loose ....