Hi i run a 250cc 4 stroke air cooled.changed main jet 140 to 115 pilot jet 38 stock.cant figure out how to tune it.the spark plug is black.even play with needle
But main problem is i even removed the idle screw out and even it continue to idle high and low and doing pop up backfire.please help
But main problem is i even removed the idle screw out and even it continue to idle high and low and doing pop up backfire.please help