yeah you need to wind baqck and then lock the spring (with a honda tool/homemade tool)
if you try really hard you lock it with a screw driver although I used long phillips head drill bit, a tiny spanner and some duct tape to stop it winding back down afterwards
Would be better with a new gasket (costs next to nothing) but give sealant a go (can always refit if it leaks); the pressure doesn't seem to high here so will prob get away with it, I know someone who left the end bolt off for a few weeks - it didnt leak much