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Motorcycle Repair/Cam timing on 72 CL450


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?

Paul P.

Paul, there are a number of discussions on the Hondatwins site:  with good photos and description.

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  \

Bill Silver  

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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