Camshaft oil leak

I have a significant oil leak at the plug that covers the end of the camshaft. I tried to pull it out to see if I can replace the o-ring or something, but it won't come off, and I don't want to break anything.



I've searched extensively on the forum and even disassembly diagrams but I can't find out if that plug can be removed as is or if it is necessary to disassemble the head cover.

How can I unmount it?

I have never pulled a 400 top end apart, but in looking at partizilla   www.partzilla.com/catalog/kawasaki/motor...covers-76-77-kz400-d
there is  clear silicone used as a gasket between the head and the cover which covers the cam end cap..  I do not know if you have to pull the cover off and clean and re-due the silicone gasket or if you can just leave the cover on and attempt to seal up the cam end cap; 

Apply liquid gasket on the cylinder head cover o-rings.

 

ebay.com/itm/301708784373

Thank you all for your comments. However I still don't know if that plug can be removed without open the head. I drive the bike daily and I plan to open the engine soon to check several things (balancer chain, timing chain, joints...) but I would like to fix it temporarily so I can use the bike while.

I had thought about sealing with gasket paste from the outside, or maybe silicone (if the plug can't be removed)

The plug can´t be removed without open the head, so do a temporarily liquid sealing from the outside.

wrote:

The plug can´t be removed without open the head, so do a temporarily liquid sealing from the outside.

Give it a good wash down with brake cleaner first, this will give the best chance of sealing 

It is understood. Luckily I didn't force it...

I'll clean and seal, thank you all.