I would start by adjusting the valves, with you asking "what valves" makes me wonder if they ever have been adjusted properly
Check out "Motocheez" on youtube, he has some great videos out on the HAWK... make sure you "watch and read" anything that pops up in his videos, he has made a few mistakes here and there but he always corrects them... sometimes he corrects the problems with wording that pops up on his videos
Either way, watch this video, and set your valves (with an ICE COLD engine)... get back to us if it helps any or not
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