ZX6 2000 rocker cover gasket

After doing the shims a few months ago the rocker cover is leaking at the front left.
I put sillicon where it says to, thats not where its leaking anyway.

Didnt use any gasket goop, I guess the rubber has gone a bit hard and isnt sealing properly.

Should you usually replace this gasket, or just put goop on it?
Will find out what it costs and how long it takes the shop to get in stock, but if its something stupid will the goop do?
Pulling it all apart now to do over the next few nights.

After doing the shims a few months ago the rocker cover is leaking at the front left.

I had the same problem on my own ZX6 the one time I sleepwalked through a valve clearance check and didn't properly clean the grit which accumulates around the protruding lip of the cam cover gasket.

Pulled the bike apart again, cleaned and degreased the sealing surfaces on the gasket, head and cam cover properly, reassembled, no more leak, and no need for any kind of gasket goop.

This was clean, I was very carefull cleaning it when I did it.