ok gotchya. yea man somethin aint right. cooling system or dome specs and carbs or an accumulation of all.
I dont think i seen what domes you have in there or what compression, squish, cc etc...
small carbs like he^^^said. And I think your lean on the mains. Dont even waste your time doing plug chops. just jet it up to see how it responds.
My cub runs at 150-160 degrees all day dunning and 175 when dragging.