filler

I'm thinking of replacing the stock oil filler plug on my Gen2 with an aftermarket item. Can anyone confirm the diameter / thread pitch for the plug, please?

Ok seem to have got water in the oil... I just washed the bike with a hose and after washing I started the bike up to help dry it. I noticed some white scum in the view glass, I then took the filler plug out and I can see that some water has either got in through washing (how?) or ive got a...