i presume harescramble the same as enduro in the uk ,what time do you ride for? when i was doing enduros ( 3 hours ) on my kx250f i would have to fill up mid race and still have a bit left at the end , dont think i would like a bigger tank ,makes it heavier and not so easy to flick through the wood sections . when i had my kx250 with a larger tank i still had to fill up through the race and it was a monster to handle with the extra fuel! i rode in the over 40s expert class , without being rude it depends how quick you ride on the fuel consumption front. we do sometimes get a "sprint scramble" event but thats two 1 hour races ( not back to back).