66B Harley - casting questions

[tractorboy]

Always enjoyed the detail on this model and was having a look at a couple of mine and noticed a difference in the engine castings.
Not sure if this has been covered before (couldn't find anything in forum).

On these model the top of the engine, between the cylinders and above circular carb adjustment? there is an open gap

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more detail here

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On this one that area is infilled and solid

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Also looking at the crankcase cover some models have 3 ribbed lines and other have smooth finish (though does look to be remainder of lines on a couple)
smooth (screenshot photos)

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ribbed - also on 2 at the top

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Is this due to wear on the casting dies?

[kerbside]

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Tractorboy here is two variations that you do not mention on the side car base.

George T.

[tractorboy]

Thanks George, I was aware of those 2 as Nick had on variations page:

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My query was more in line as to whether the engine casting differences and crankcase castings that I showed were variations or due to wear on the production dies and hence not variations.

[DrJeep]

Is this due to wear on the casting dies?

I think the infill between the cylinders looks deliberate. I only have this one, which I've owned from new. It's really about two-thirds of a Harley, as the front forks broke sometime in the 1960s, but I obviously still liked it, as it's been around ever since. It's quite a sharp casting, with little sign of flashing in the other gaps but neat infill between the cylinders. Sidelighting from a torch does highlight the dust! I think that's a good spot, Rodger.

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