Have had my valve cover off a couple times. No issue at all.

 

If you have an 09 klx get a new valve cover gasket ahead of time so your not having to go get one to finish the installation, damn thing shrinks once you pull it off.... The replacement gasket doesn't shrink, as I have rechecked the valve clearance and reused the newer one with success reinstalling it.

You can use a large hose clamp for a ring compressor.

 

That is the issue I had with my 09. It had shrunk and would pop out of the groove. I will have to order a new one.