1956 Petcock on KH

[MTaylor]

Looking through another forum, I read that the 56 K has a one-year-only petcock. Thought I had just about everything for my bike, but apparently not.

Does anyone know what the difference is? A picture would be even better.

Thanks

[Yard Dog]

Mike,

I'm aware of several 56 only pieces, but I can't say the petcock is one of them. How about a link to that forum discussion ?

How did the 57 turn out ?

Jack

[hennesse]

Looking through another forum, I read that the 56 K has a one-year-only petcock. Thought I had just about everything for my bike, but apparently not. Does anyone know what the difference is? A picture would be even better.
Thanks

Mike,

I don't think there's any special 1956 petcock, but from what I can gather, the late 1956s MAY have had a special tank and crossover connection. Here's some preliminary information gathered from the parts books and usual suspects. We'll keep digging.


The two-flippered petcock came in two varieties – the 62125-50 with the threaded lower end (1952-56 K/KH) and the 62125-55 with the hose barb lower end (1957-later Sportster). The part number suffix indicates the first year these were used on the Hummer-series bikes. The threaded petcock was used on K/KH with the Linkert M carburetor with threaded inlet fitting, and the hose barb petcock was used on Sportsters with the Linkert DC carb, with hose barb inlet fitting. No surprise here.

The 1956 and 1957 Spare Parts Catalogs show the 61006-52B gas tank for 52-56 K/KH (male threaded fittings on the bottom) and used the metal 62355-52 crossover line; and the 61006-57 tank for 57-58 XL/H (90-degree hose barbs on the bottom), and used the rubber 62355-56 crossover line. No surprise here either.

The 1959 Parts Catalog tells a different story – it shows the metal line was used from 1952 to Late-1956, and the rubber line was used from Late-1956 to 1965+. However, it also shows the 61006-52B gas tank, the same one that was first shown in the 1955 Parts Supplement, then the 1956 Parts Book, as used on 52 through 1956 K/KH.

But the rubber hose would not work with the male threaded fittings on the K/KH tank. This suggests that something else changed in late 1956 – perhaps the gas tank. It couldn't have been the 1957 Sportster tank, as the petcock would be on the wrong side. Also, the tank emblem mountings would be wrong, and the Sportster tank is shaped a little differently, to accommodate the taller Sportster cylinder heads.

Jerry R. thinks there was a "transition tank". What could this have looked like? Perhaps it was just a -52B KH tank with hose barbs instead of male threaded fittings. On the other hand, it could have been a Sportster tank with the recesses for the XL cylinder heads, but with the petcock relocated to the other side. Both make some sense, as Harley was gearing up for the Sportster in late 1956, but which one is correct?

To confuse things even more, the 1963 Parts Book shows a 61006-52C gas tank for the 52-56 K/KH. (Sorry, I don’t have the 1960, 1961 or 1962 Supplements). What was this? Possibly a late attempt to document the "transition tank"? Or perhaps a one-size-fits-all universal replacement?

At this point, all we know is that something changed in late 1956. Just what changed, and how late in the year, is not well understood.

Stay tuned,

--------------
Notes on the K/KH metal crossover lines

Roger M. thinks there were at least two versions of the metal 62355-52 crossover line, one being for the early 1956 KH to accommodate the frame change. There may be an additional version as well.


Notes on the 1957 Sportster tank

Jack R. says the early 1957 tanks had a petcock location almost an inch rearward of where they later settled. It's not clear when it moved, but Dave C. seems to think as many as 500 left Milwaukee that way. Jack agrees, as he has found three of them.

[dr dick]

Sorry, I don’t have the 1960, 1961 or 1962 Supplements.

i do.
60

61

62

[strong56KH]

There were two versions of the petcock. One has shoulders on one side below the base of the center wrench flats, the other does not. I believe the shouldered version was produced later after 1957. The 57 XL at the H-D museum has the unshouldered version and I have seen several 56 K-models with the same version but with threads for the fuel line. Elvis 56 KH at the H-D museum has a shouldered version and threaded for the fuel line. This may have been a later replacement. Reproductions are made of both versions. V-twin produces a leaky shouldered version.

[JerrryR]

Hi Dave,
What I had learned from Roger M. is that there were at least two metal gas tank crossover line versions. Since the second one would work in place of the original one they didn't bother to change the part number, 62355-52. As best as I can tell the first version was used on the 52 and 53 Ks and was configured in what I will describe as one plane, flat, the parts book depict it in this fashion and the factory 52K pictures show it. These by the way are the versions "Old Dude" is selling.

PN 62355-52.jpg (28.72 KiB) Viewed 17197 times

52K Crossover Gas Line Vertical.jpg (26.1 KiB) Viewed 17197 times

As best as I can tell Harley went to what I am going to call a two dimensional gas tank crossover line in what I believe to be 1954. This would make sense for clearance reasons as the KH cylinders were a little taller. I could use some help here verifying or disproving my next statement. It looks like in the "Legend Begins" book as if the "loop" in the crossover line is facing the rear in the 54K picture and to the front in 55 and 56 as can be seen in the following image of a 56 K.

56K Gas Tank Crossover Line.jpg (15.41 KiB) Viewed 17197 times

To the question of was there a transitional gas tank in 56 I believe so. The 57 Parts Book shows for the "Gas Tank Connector Gas Line":
PN 62355-52 52 to late 56-All K models
PN 62355-56 Late 56-Model KH, 57 Sportster
Since the Sportster used the rubber push on gas line tank connector this information indicates so did the late 56K tanks. My GUESS would be that they started producing the Sportster tanks with the recesses on the bottom and the push on crossover rubber line fittings and simply put the petcock on the appropriate side for the remaining late Ks.
Have a great day,
JerryR

[EKHKHK56]

My 56KHK Gas Tank is all factory stock. It has the 1956 Tank Emblem Mounts, Left Side Petcock, XL rocker box recesses and Rubber Hose Crossover Pipe. So no doubt or mystery on that. These also would have been used on 57 KHs except with 57 tank badge mounts. I saw 57KHs listed on a factory production sheet and I have seen 57KH cases before way back. Thought they were bogus until seeing the production sheet listing about 30. Any more ideas on that? Cheers Folks, Erik K

[hennesse]

WOW - what great information!

Erik's 56 KHK seems to confirm Jerry's theory on the late-1956 transition tank being a Sportster tank with relocated petcock.

Erik's sighting of 57 KH cases seems to confirm what the The Legend Begins says - that 90 KH's were produced in 1957. I wonder if any complete bikes still exist?

Jerry's observations of the metal crossover. - yes, the photos in TLB shows the 54 with the loop towards the rear, and 55, 56 with the loop towards the front. I wonder why? Could there have been a problem with engine heat when facing backwards? Perhaps this just a prototype bike quickly put together for the advertising photos?

1954 KH from TLB

DMH_0000-72-720x576.jpg (51.84 KiB) Viewed 17168 times

In my Department of Useless Petcocks, I found all 4 combinations: threaded, non-threaded, with shoulders, without. I believe these are all original Harley. Here's a photo of the two threaded ones. You can see one of the shoulders on the petcock on the right. The shoulders are on the Reserve side on both the threaded and hose barb ones. The one on the left came with my 54 (and I believe it to be original to the bike) does not have the shoulders. Unfortunately, the rust and glop in the tank from sleeping for 25 years plugged it up, and I can't get it to flow at all.

No shoulders (left) and shoulders (right)

DMH_005578-arrow-72-720x576.jpg (43.17 KiB) Viewed 17168 times

Final question: Did Harley put a gold chromate finish on the petcocks?

[EKHKHK56]

1956 KHK 5-56 date Gas Tank

[MTaylor]

My 56, which has the original tank, has no cutaway for the Sportster rocker boxes.

I found the reference to the 56 only petcock in one of Dave Swanson's posts on the Caimag site. His 56 KHK has gone through AMCA judging a number of time and achieved the highest designation, which of course I forget. If you haven't seen that build thread, you should take a look.

My tank is set up for the threaded crossover.