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In a break from the 21F restoration I was having a coffee and looking over the 23F "project" which sits on a wooden stand in the shed.
The soldered-on piece on the top frame rail in front of the seat post has always been missing, so there is no factory stamping on the frame. In the absence of a code and number, do the following features confirm that it is, in fact, a 23 frame: the attachment of the top tubes behind the seat; the muffler brackets front and rear (still covered in years of road dirt, carbon, oil and what looks like lichen (!); and the rear cylinder brace attachment under the lower of the two top frame rails?
P1030594 (2).JPG
P1030589 (2).JPG
P1030587 (2).JPG
P1030593 (2).JPG
The holes for the rear cylinder brace are noticeably more elongated than those on the 21 frame. I'm sure I read somewhere that this was to accommodate the 1923-on cylinders which were fractionally taller than the 17-22 cylinders, and that these taller cylinders were stamped on the base flange. Have I got this right?
If this is correct, what and where are the stamping marks I should be looking for on my cylinders? A photo would be very helpful. I can't find any marks on the cylinders which are now on the 23 motor but, of course, in the last 98 years the cylinders could well have been replaced.
As can be seen in the last photo above, the cylinders sit high under the brace bracket but that may be only because they have the compression plates for sidecar use installed
P1030592 (2)_LI.jpg
As always, any clarification and information will be much appreciated.
Mike
The soldered-on piece on the top frame rail in front of the seat post has always been missing, so there is no factory stamping on the frame. In the absence of a code and number, do the following features confirm that it is, in fact, a 23 frame: the attachment of the top tubes behind the seat; the muffler brackets front and rear (still covered in years of road dirt, carbon, oil and what looks like lichen (!); and the rear cylinder brace attachment under the lower of the two top frame rails?
P1030594 (2).JPG
P1030589 (2).JPG
P1030587 (2).JPG
P1030593 (2).JPG
The holes for the rear cylinder brace are noticeably more elongated than those on the 21 frame. I'm sure I read somewhere that this was to accommodate the 1923-on cylinders which were fractionally taller than the 17-22 cylinders, and that these taller cylinders were stamped on the base flange. Have I got this right?
If this is correct, what and where are the stamping marks I should be looking for on my cylinders? A photo would be very helpful. I can't find any marks on the cylinders which are now on the 23 motor but, of course, in the last 98 years the cylinders could well have been replaced.
As can be seen in the last photo above, the cylinders sit high under the brace bracket but that may be only because they have the compression plates for sidecar use installed
P1030592 (2)_LI.jpg
As always, any clarification and information will be much appreciated.
Mike
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