I'm getting ready to check my own valves for the first time and i noticed that the instructions in the service manual show putting some silicone sealant on the head only on the cam chain tunnel side? Is that correct? Can you use any silicone sealant or do you have to buy the Kawi stuff which I'm sure will cost me double. Do you have to always replace the head gasket when checking the valves?? Seems like they recommend replacing the head gasket.