How to increase the dc motor's speed(andFrequency)value more than255(and64KHZ)?

It is still the same without delays . And now only last button works the way I want ;but others doesn't work ( okay leds are on and off when I press button ;but motors don't move at other 2 buttons and while pressing other 2 buttons they noise " tick tick ;or a strange noise ". How to fix it ? thanks.

Would you make some adjustments on my codes please to solve and fix this issue ? thanks.
( first button is for tank movement forward; second button is for tank movement backward; third button is for tank body rotation to turn its around with using debouncing )

Not:
I tried without debouncing ;but it gives only noise and " tick tick " or strange behaviours happening ( start to move after a while then stop then move again while holding the button; thus I was started to use debouncing but new problems occured now that I mentioned at my first paragraph above ). Friends Please help me to fix this issue, I really need your help, thanks again.