Thanks Andy, I put everything new to the engine when I restaured it , and I would have liked to put the news rc valves on it. They work well but I don't know if the shaft with the cams will get slack over time. Many NSR make a clinking noise and it is from the rc valves, I have been able to verify that pressing the shaft with a finger stops making that noise. I don't remember if Honda recommended changing the valves when it had a certain clearance.