Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models K KR KRTT XLH XLR Steering Head Castings

K KR KRTT XLH XLR Steering Head Castings

Post Sat Mar 01, 2008 1:59 pm

Posts: 4
Hi to all -- i am a little bit confused about the head castings that have been used on the different frames and how to tell the differences.
From all the information I have I still can't figure out what was factory and what not. As far as I can tell there have been three versions for the XLs to the late 60s -- one for the XLHs (casting nuber ends 56), one for the XLCHs (ends 58) and one for the XLRs (ends 57R).
The K-models seem to have three castings as well -- one for the early K and KRs (casting number ends 52), one for later KRs (I guess 56 and later) and one for 56 KHs (ends 56) -- plus the 57R for later KRs.

So far so good -- confusing is, that all the wheelbases are that different, that there must be a difference in rake plus the fact, that the earlier castings seem to have less metall between lower end of the steering tube and lower tubes. I added some photos to show what I mean (Patrick, I hope you don't mind using some pictures from your site ...). Still you can find later KRs or XLRs with the "smaller" Head casting, that looks like the earlier Ks ....

Neck Difference.jpg
difference necks
Neck Difference.jpg (10.61 KiB) Viewed 2201 times

Now, another thing is that the non racing frames from 56 on are "gooseneck" style (what is actually the difference between the KH/XLH and XLCH frame neck casting -- as they have different endings?). If you look at the 58 XLH frame I have, you can see that there is some kind of "optical extension" of the lower tubes from the front tank mount to the top of the steering head.
KH / XLH Neck
DSCF3093.JPG (106.81 KiB) Viewed 2199 times

If you look at the 56 KH or propably KR frame I have, you can not find it although the neck cating end with -56 (The bad thing about this is, that the former owner grinded the number away, thinking it would be the VIN -- so I can not compare it to the XLH frame).
KH / KHRTT ??? neck
DSCF3072.JPG (117.52 KiB) Viewed 2191 times

For me it seems that there must have been at least another version of frames (my frame is chromoly, but not thinwall, has K-model cast motor mount but clearance for a XLH engine, intermediate tube extensions on the front lower tubes, dated A6).

Then you can find racing frames with "steering head job done" mostly lowered or deraked, but also versions with bigger rake for "stability at speed".
If you look at Patricks KHRM photo from the KR frame post you can clearly see the intermediate tube extensions and it looks like a gooseneck casting (from the height of the upper fork tree) ... you can find the same frame in Allan Girdlers "Harly Racers" on page 50. It is a picture from Fumio Itoh on a KHRTT -- you can clearly see the gooseneck and it seems to have intermediate extensions.

Still not clear what steering rake was used, was it common to change the steering head on racers or even factory standart? Did they grind the lower area of the casting? How many castings have been used?

I now this might be a look and very specific posting, but I think this is the best place to ask ....



Posts: 591
Location: Crewe, Great Britain

Gosh, where to start answering since they are other factors at hand!!!

As far as I can tell, here's the evolution of steering head casting

a) -52, on chrome moly frames, K and KH, 1952 till 55, also used on early KR/KRTT frames, 1952 till 1957, no goose neck, goes with thin webbed seat casting. As far as I know, no year/month codes on these.

b) -56, 1956 KH and 1957 till 1966 XL and XLH, 1958 to 1969 XLCH, much thicher steering casting for provision of tapered intermediate tubes on bottom frame loops. The XLCH frame was recommended by the factory for Daytona KRTTs in the parts books. Have year/month code on right of seat casting.

c) -57R, new race steering head introduced for KR, KRTT, XLRTT when the K frame was deleted, slightly reinforced as noted, my photo of 69 XLRTT. Goes with post 56 reinforced webs seat casting and top tube squashed underneath for OHV clearance on rear cylinder assembly.

All these head castings have the same steering angle. The rake was changed by modified top and bottom trees: all the racers kept the K geometry, except daytona KRTT when used with XLCH frame

Naturally, there's always an exception to confirm the rule, I've seen one 57 KR frame that has a goose neck!!! Could be a repair, could be from the factory, who knows... Could be the one you have with photo!!!

The only difference between a 56 KH frame and a 57 XL frame is the top tube motor mount: cast on the KH, stamped steel on the XL. Actually, the introduction of the stamped one could have been on late 56 KHs, somebody could check their frame codings...

Will check later on my frames, but I also think the "optical extension" comes later in the mid sixties...


Posts: 217
Location: Palo Alto, CA

I just checked the frames in my living room here ( :shock: ) and can report the following:

One is a frame known to be from early 1953 (engine belly numbers are 552-XXXX; VIN is a very low number), it has a -52 head casting (first few numbers not very legible unfortunately) with the "cutaway" immediately below the lower bearing cup.

One is a late 53 frame, date code 3J. It has a -52A neck casting number, as does the 54 KH frame I have (pictured below). No casting number on upper engine mount.

-52A neck casting from 54 KH frame
fcd0_1.JPG (13.25 KiB) Viewed 2072 times

So this would suggest that this -52A neck casting was perhaps used late-53 to at least 54 or 55.

Do you think the date codes came in part way through 1953?
Last edited by suicideshovel65 on Wed Apr 13, 2011 1:37 am, edited 1 time in total.

Posts: 217
Location: Palo Alto, CA
Oh, and judging by the weight difference in these frames, I'd say the -52A frame is not chrome moly.?

Posts: 591
Location: Crewe, Great Britain

Hi Suicide Shovel,

I have 2 early "no goose neck" K frames, one definitively chrome moly: it "pings" rather than "pongs" when I hit it, not genuine KR but it's been raced on the flat tracks, discarded braketry and such, it's on my KHK, the other, acquired recently, seems a bit heavier, but that's just from memory!!! Neither have frame codes... I'll try to weight it on my wife balance and compare with my stored March 59 CH frame...


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