HD cylinders

[philippe]

hello
can somebody tell me the difference between 1915 and later 1915 regarding cylinders
i try to make comparaison using pictures but doesn't see any evidence!

[knucklehead 61]

compare the fins around the exhaust valve cover.
15 are curved.
16 & up are flat.

[philippe]

thanks for your reply
I don't understand clearly what you explain, when you sau exhaust valve cover , where is it ?

[philippe]

compare the fins around the exhaust valve cover.
15 are curved.
16 & up are flat.

you are talking about the vertical or the horizontal fins?

[knucklehead 61]

the horizontal fins near the bottom of the cylinder. they almost touch the valve spring cover on a 15, but are not close on 16 & up.