Cam chain with complete tensioner too. HD chain not expensive either. Check the status of cam sprocket, not many $ either.
clutch can be replaced later without pulling the engine, but easier to do when apart.
There are gasket removal chemicals that work fine, easier to scratch the residues after treatment with chemicals. Less risk to scratch the surfaces.
All sealing and ALL O-rings keeping up the oil pressure from pump and all the way to head... There is a thread about that, explains clutch hub mod too. (extra holes).
Make sure that all 4 o-rings under the cam towers sealing the oil transport to cam and rockers will be there.
I noticed that the o-ring can be too thin, not reaching over the edge on head so it will create a seal with pressure against cam towers. My head needed closer to 2mm thick. The kit from Yamiya had thinner, not over the surface.
Hone cylinders, check pistons if the rings fits well without play up-downwards. Heavy driving direct when cold can affect the pistons this way. don't ask me how i know that
Valve job, cut seats + valve/guide sealers. Head cylinders flatness OK, no deep scratches?