So I install the 478 Athena kit in my WR450. Everything goes good. I get everything together. I turn the engine over by hand. She is good! I get the spark plug in and turn the engine over with the starter and I hear this loud knocking.. I remove the plug. Turn the engine over with the starter again....no knock. Am I doing something wrong? I am running the same plug as before. NGK9EK. Has anyone else came across this issue. I've searched but found nothing.