Motorcycle Repair: Cam timing on 72 CL450, punch marks, bill silver

Question
I'm reassembling a 1972 Honda CL450 engine. I have the cam marks on the bearing boss marks. (Exhaust cam mark just barley visible). Now the dynamo is lined up with "LT" for left top dead center. Now, my problem is....the left exhaust valve is slightly open. Both valves should be closed.   My Clymer Shop Manual states that IF off even one tooth on cam timing, the valves will hit.
Can you help me?

Thanks,
Paul P.

Answer
Paul, there are a number of discussions on the Hondatwins site:

http://www.hondatwins.net/forum/viewtopic.php?f=51&t=5253&start=0

http://www.hondatwins.net/forum/viewtopic.php?f=5&t=12231  with good photos and description.

http://www.hondatwins.net/forum/viewtopic.php?f=51&t=16177

http://hondatwins.net/forum/viewtopic.php?f=51&t=11495&start=20

Bear in mind that when the piston is at TDC only two valve events can happen... Compression (both valves closed) or Overlap (both valves slightly open). Remember to orient the valve adjustment shafts so that the punch marks are both pointed away from each other  

/  O   \   /  O  \

http://www.rivetrestorations.com/Motorcycles/Tech_Tips/CB500T_Engine_Adjustments

Bill Silver