Kawasaki FH721V-CS34-R Head Repair

I bought a JD lawn mower and it had low power but a mouse had chewed through the coil wire. So I thought it just needed a new coil.  I put the new coil on it and it didn't fix the problem.  I took the valve cover off to see if if I could see any internal problems and I found that both push rods were bent.  When I was disassembling it I noticed some valve/head problems.  So I am replacing the head and installing all new parts on the head.  I was wondering how to adjust the valves?