cjsdad 18 #26 Posted November 25, 2013 Not a two-cylinder story, but after putting my K181 back together it also had a bit of a knock. I changed the oil, adjusted the carb, etc. and the knock continued. It was only at low speeds just above idle. Turns out the timing was off causing detonation. I had replaced the points pushrod with one of my own creation and the points were operating back to factory spec. If the cam lobe wears down on the twins like in the K181s the points will open and close different than when factory fresh causing the timing to change. If your fuel was getting old that could have an effect too. Share this post Link to post Share on other sites