I have a 78 XL125 Honda i have to change my spark plug every second or third ride.... i don´t know what the problem is?is it the engine or the coil that´s not running good? The spark plug gap (the side that you turn into the engine) will be all black and wont make any spark ....But when i put it into my pocket bike it will make spark ...so i am not sure what the problem is ....any ideas?