Valve/cam cover oil leak

I swapped valve shims on an XJ650 maxim last summer. It runs great now but, there are oil leaks even with a new gasket, mostly at the cam end rubber plugs, but also at the front of the cover. I am going to going to pull the
cover and clean the gasket and mating surfaces. I would like to use some kind of oil proof silicone this time.
Can anyone recommend a product that they have used that worked ?

 

What year?

 

Permatex oil resistant black RTV.
The half-moons get some no matter what year it is (gaket types vary by year).

 

It is covered in this thread
Bigfitz's AIRHEAD VALVE ADJUSTMENT with Pics - parts I & II

I do assume you are talking about your 82 xj650
the donuts on the valve cover of the yics motors tend to dryout replace them they keep pressure on the valve cover to help seal gasket. I found that replacing donuts stoped leaks
High-Tack spray gasket sealer for cover in the groove glue gasket in place then smear head side with sil-glide silicone grease.
torque to spec

you can use black rtv oil/fuel resistant type in place of sil-glide

 

You can buy this or another brand aviation gasket sealant at your local auto parts store. It stays soft and you can get it apart later. A thin coat does the job and no RTV getting squished into the engine. NO LEAKS!

As in the previous post, the half moons get RTV. You may want to buy new ones as the old ones could have shrunk.

 

Where did you get the gasket from? I got an aftermarket one and the half moons cracked when I tightened the valve cover down. Maybe I over torqued, but when I used an OEM gasket from Len the leaks stopped and it has been fine for a few years.

 

Weather permitting, I'll pull that cover tomorrow. I think I used that brown gasket shellac on the head and half moons and Harbor Freight's
knock off of permatex black all along the edges of the cover including hold down donuts. I'll clean all the old stuff off and try those suggestions.
thanks

 

+1, for sure.