Thats a little lean always take your colour off the centre probe But thats how 4t are restricted smaller jet ( if yours is std)
fuck knows what mine is but its slow as hell propper struggles to get to 40 changed oil n oil looked new n changed spark plug n the plug came out looking like that dunno what i can do to incrase the speed without pissing around with the carb seen as i know nothing about carbs apart form they pull petrol into the chainber from the stroke of the piston going to b.d.c