Yep, it took about a day and a half as one of the guide rails for the chain broke. I done the job with Modulator outside my house.
It had a slow leak between the cylinder and the water jacket, this was pressurising the coolant and leaving a nice mess around the coolant tank vent. Compression test came out fine and the engines performance was fine. All it did was run very slightly hotter than usual.
If you got a problem with the gasket just don't leave it as it can do all sorts of damage. There was a bit of a nick on my head where it was starting to corrode. Just caught it in the nick of time.