Hi everyone! Im new here and new to motorized biking aswell. i recently completed my modern style board racer inspired project with a chinese engine Kit. I was riding and my engine(2stroke 67cc Slanthead) lost power and after 100-150feet it stopped running. It would still rev after i got it started with some effort but the engine was making a grinding noize and so i stopped it. It was on its first tank of gas and i used 18:1 break in mixture. could anyone please give me some advice on what could cause this problem? the piston still moves but it doesnt want to rev and it wont idle for more than a few seconds.