Hi Grumpy, have tried pushing the pin in with a punch a couple of times, couldnt see or feel any movement but did end up with a sore thumb when the punch slipped off once. ( stop laughing ) Have done some measuring for you, across the cam is 1&21/64 of an inch,, across cam and pin is 1&23/64 of an inch, which means if my maths is correct the difference is 1/32 of an inch. Just scrolled through our conversation so far and stopped on the firstpicture you sent me off the decompression unit and noticed i dont have the thrust washer, it not being there wont make any difference will it? Have supplied a photo of the exhuast tappet, is the mark on it meant to be that way? [Linked Image]