I'd get rid of that single carb shit ASAP.
Do a WOT plug check and see what color the electrode is..
White/grey = lean
Tan = good
Brown/black = rich
Being way too lean or way too rich can cause overheating. Just need to see where you're at.
Dirt bikes don't hook harder than ATVs.
They appear to go better because combined rider and bike weight is close to 200 pounds less than their ATV counterpart.