Moffatt

hi i am trying to remove my barrel on my dt125r i have removed the hed and 3 of 4 nuts securing it 1 of the nuts is extreamly rounded and i cant remove it has any one got any idia how i can remove it it is the nut that also holds the clutch cable tentioner so it is under a lip so i cant get to it with extractor tools

i have the same bike myn will easily do 80 an ocationaly push 85 i have a full dep system but original air filter to get moor top end try increasing the size of the frount cog and take it to a dyno to have the fule and air mixture tweeked to optimize proformance