83 honda atc 110 put in low gear seems to run out fine but put in high gear not so mu

[bigfish]

ive got a 83 Honda atc 110 I can put in low gear and seems to run fine threw all gears but when I put it in high gear it kinda acts like its not getting enough fuel for the higher rpms and sputtering out when I open the throttle all the way any and all help would be great thanks.