Peter Ronney
XS400 Enthusiast
Hi everyone! I took my 1978 XS400 out today. All of a sudden it started making a terrible loud tapping noise and it sounds like it’s coming from the right exhaust valve (sorry for no video, I didn’t want to risk harming the engine). Of course my first thought is the nut worked itself loose and undid my valve adjustment job. Took the access port off, the nut was tight. I’ll go over all my valves tomorrow when the bike has cooled down fully anyways. I pulled the plug to see if there was any damage if it bent a valve or something and thankfully not. Are these interference engines? I want to make sure it’s OK to start the engine as is when I get into it again. It seems like a this is a common problem on the forum, has anyone had this problem and if so what was the solution if not valve adjustments? Thanks!