Earliest K Frame and a Question/Theory

[JerrryR]

Hi All,
First I would like to make my case for what I believe to be the earliest of the K frames being as built and not repaired. Second I ran into a frame anomaly today that had me smiling and a theory about it. I will do this over the course of two posting since I have 6 images that I need to post. The first three pictures are from the OSKRG report on frames that many of you contributed to. The report by the way is on this website under the Technical heading. The 4th picture is what I will call my proof that these earliest of K frames did not have the fender strut support casting break and steel pieces welded in as a repair. The image is from the September of 53 Enthusiast Magazine and clearly shows the welded on steel strut supports. In addition I have two of the threaded downtube frames and one with the welded struts and smooth bore downtubes. Today I took a road trip and examined a third threaded downtube welded strut frame. Finally the seat casting on these early frames are slightly thinner than on the later frames where the fender strut supports are part of the seat casting. My next post will show the 4th picture from the 53 Enthusiast and address the frame anomaly I ran into today.
JerryR

Snipped Early K Frame Welded Strut Support Threaded Downtube 1.JPG (146.87 KiB) Viewed 13444 times

Snipped Early K Frame Welded Strut Support Threaded Downtube 2.JPG (133.75 KiB) Viewed 13444 times

Snipped Early K Frame Welded Strut Support Threaded Downtube 3.JPG (184.14 KiB) Viewed 13444 times

[JerrryR]

This is the follow up posting to my first one. Below is the Enthusiast Magazine image showing the welded steel strut supports.

Snipped Early K Frame Welded Strut Support Threaded Downtube 4.JPG (96.9 KiB) Viewed 13440 times

Here is the frame anomaly I ran into today and what I presently believe. I believe all 54K frames were either what I call the "welded neck 52 casting" or the -52A neck casting that had the same geometry as the factory reworked/raked -52 neck casting. I believe all street Ks for 52 and the 53 model years used the -52 neck casting with no modifications to it. The following two pictures are what I ran into today. An "I3" date coded frame with an uncut, unmodified -52 neck casting. See below.

I3 Optimized.jpg (160.21 KiB) Viewed 13440 times

I3 Optimized.2.jpg (181.84 KiB) Viewed 13440 times

Let me start by saying I don't know if what I am about to say is correct, it is what I think for now until evidence presents itself to cause me to think differently. I believe this frame was sold as a replacement frame for the 52 and 53 Ks that used this geometry for their front ends. I still believe that all the 54s and newer used the new rake angle for their frames and this frame was never intended for use on a 54K??? Has anyone ever seen or does anyone have a date coded frame appropriate for a 54 or newer bike that has the unmodified -52 neck casting?
This one has me scratching my head.
JerryR

[EKHKHK56]

Jerry, I am sure the first frames are factory with tabs welded, have seen many examples long ago including the earliest version. I used to have one. The strange thing is I have a 53 with that rear set up also. And 52 frames without it. The 53 one must be a KRM? It has not ever had tabs for side oil tank and tool box-coil cover. Erik K

[sportsterpaul]

Good stuff.
My J3 (October 1953) frame has the -52A neck casting.

I do note the first picture you posted (from the frame pdf) seems to look more like a V-Twin seat post retaining plate, which is flat. One OEM that I got on eBay has a rise stamped in it to clear the main frame tube/backbone. You can see it here:
viewtopic.php?f=8&t=184&start=10#p1113

So could it be possible that they had threaded seat post tubes, on the early frame, then took out the threads to save cost and used this plate with the "bump" on it to clear the main tube, and then to reduce cost of that plate, relived the frames so a flat plate will fit?

I like your theory about a service frame that was hacked together to support the 52/53 front forks that have the non-parallel stem in the triple tree. It could also be Harley found 20 or thirty triple clamps under a table, and hacked up 20 or thirty frames so they could use up the triple clamps as opposed to putting them in the service parts bin.

Does anyone know what the handling difference was between the two front ends? It looks like they increased the rake for stability and then went to the parallel fork stem to get the trail back where it was, so you can turn bike. My understanding is the early frames were brazed or silver-soldered, so I can see racers and hard-core owners just swapping parts around, and it was not the factory that did this.

The work you guys have done on this is awesome. I was disappointed when Harley never responded to my request for a BOM (bill of materials) for the old bikes. Now I see that they may not have had one-- they just put together anything that was laying around the shop that day.

[thefrenchowl]

All frames from all makes that involve fixing tubes inside castings can only be done with silver content rods... Brazing with bronze only rods will not have the penetration needed,

In fact, a silver brazed frame will be stronger than one just bronze brazed... So all K, KH and Sportsters frames up to 1981 have been silver brazed...

As for early K frame, I will look at mine again...

It seems to me to be pretty random, mine is all cast but with no frame code so probably late 52 and no butchery on the steering casting...

So poor castings cut down and repaired to be re-use as they were needed, meaning full cast seat casting mingle on the assembly line with repaired ones with welded square bits...

As for the 53 Enthusiast illustration, the shot could actually be very early, 1950 or 1951... If we could find its Pohlman number, I could tell you the filing date straight away...

Patrick

[EKHKHK56]

I'm not sure why they did the weld on rear fender support mounts. Perhaps they were never cast with mounts, and were bobbed like that with a hard tail set up in mind. Just an idea. Erik K

[thefrenchowl]

Thanks Erik for that post,

It goes towards my theory that the KR idea being more important for Harley due to racing (with a flat track rigid end, no need for these extensions..) came before the K idea...

Obviously, it soon dawn on them that they needed both and their development progressed soon in parallel...

Patrick