Topic: oil thickness

[CrankyOldGuy]

I am here to eat a bit of "crow" 

Upon reading TT's response to my previous post I purchased a Honda Owner's Manual for the 1970-71 CB750K1.  Following is an excerpt from page 25 of the manual.  The bold text is as shown in the manual

"ENGINE OIL RECOMMENDATION

Use only high detergent, premium quality motor oil certified to meet or exceed US automobile manufacturer's requirements for Service Classification SD (previously Service Classification MS).
Motor oils intended for Service SD or MS will show the designation on the container.
The regular use of special oil additives is unnecessary and will only increase operating expenses.
Engine oil should be changed at the intervals prescribed in the Maintenance Schedule on page 37.

NOTE:  Engine oil is a major factor affecting the performance and service life of the engine.  Non-detergent and low quality oils are specifically not recommended.

VISCOSITY

Viscosity selection should be based on the average atmospheric temperature in your riding area.  Change to the proper viscosity oil whenever the average atmospheric temperature changes substantially.
Recommended oil viscosity:
     General, all temperature           SAE 10W-40
     Extreme, high temperatures     SAE 20W-50
Alternate:
     Above 59F   SAE 30 or 30W
     32 to 59F    SAE 20 or 20W
     Below 32F   SAE 10W"

Harry O.

PS  If anyone has a manual question I can now answer it