KHK Cylinder Oiling

Hi guys,

I am hoping for some tech advice here regarding the oil holes in KHK cylinder walls.

I am assembling the top end on a '56 KHK and noticed the cylinder oiling holes do not penetrate the cylinder wall. The cylinder base has a 0.0125" diameter vertical hole in the base that meets the 1/4" x 28 hole in the side of the cylinder base. But neither hole penetrates the cylinder wall. It is a short, 90 degree dead end hole. By the way, these are OEM cylinders and have not been resleeved.

1. Should the oil hole go through the cylinder wall?

2. If so, what should the exact diameter be?

3. Would the hole be a straight shot through the threaded hole parallel to the cylinder base?

I would be very grateful if someone could check a spare cylinder or two and let me know. A picture would be outstanding.

thanx in advance,
Cody

Hi Cody,

Just went in the garage to check my old cylinders.

The hole is .040" and dead in line with the center of the threaded 1/4" x 28 plug hole, perpandicular to the bore.

Patrick

Patrick,

Thanx for the complete response and thanx for your website.

I'm curious. I checked 3 OEM cylinders (none with sleeves) and each was absent an oiling hole through the cylinder wall. Any opinion on the history of this? I am told the KR's and 750 street K's did have the oiling hole but I don't have the parts to verify this. Since the factory omitted the oiling hole on these three cylinders, I am curious if the oiling hole is even desirable. I plan on running this bike pretty hard, so I am thinking the cylinder/piston would like a little side lube in addition to the crank oil sloshing up.

thanx again,
Cody

Hi Cody,

I had a 53 KK as well in the past, it had oilers... I do know the oil pump was updated in 56, maybe they deleted the drilling of the oilers then? Check the casting date on your cylinders and tell us.

I run my 54 KHK with the post 72 Sportster oil pump, even more flow than in 56, and still have the oilers on the cylinders, no sweat but I run it hard to say the least.

Numerous K or KH owners have reported excessive back cylinder ring wear due to too much oil (keeps smoking there...) and/or wet sumping, maybe they don't keep the bike's revs high enough?

From what I know of V Twin lube systems, I would rather think the rear cyl don't need the oiler at all, but the front cyl will certainly like it!!!

And yes, the KR racers did not have the oilers, cylinders are not even threaded for the plug... But then, they're always at max revs!!!

The breather timing has to be spot on in anycase, it's worth getting it right on the dot!!!

Regards from Patrick

Patrick,

Thanx for taking the time.

All three are -54 cylinders with date tags L (1-4), M (6-4) and J (17-5). Not sure how to read those. I am running a -72 oil pump also, half speed.

After reading your comments, I looked at my KR. It has the cylinder base flange oil screws. Couldn't see the date codes, but remember them to be -55 barrels. I do remember the cases to be 1961 castings. I've had the motor apart a few times and am pretty sure it had oil holes through the cylinder wall (sleeved barrels). I spent many hours attempting to maximize top end oiling.......too many melted pistons.

My experience with street K's smoking is (3 bikes over 15 years):
Wet sumping from sitting, running way too rich, and lugging the motor. Also, the bore is so small that some shops hone the cylinder to the next oversize rather than machining/boring them. The shops have all the right equipment to bore a Sporty at 3.000 or larger, but not the smaller 2.750. So attempting to hone to the next oversize sometimes results in an imprecise, wavy bore. Personal experience.

Thanx for the input,
Cody

Hi again, Cody,

I have one NOS KR cylinder, 55R, no oiling or plug!!! I've seen more in photos but can't remember seing one with the oilers!!! So maybe it was tried sometimes and ignored some other time???

You experience with K model rejoin mine, my old KK never had a quater of the oumph of my KHK despite similar top speed in std trim, maybe the stroke change was REALLY needed!!!

All the best from Patrick

Patrick, now that you bring it up, what was the top speed of a standard KHK ? There's very little info on this variant, as to HP, speed, etc. Thanks,
Dick

Also..

Patrick..

DId you receive my email w/photos?

George

My KHK set dates to june -55 & have the holes...

Patrick and Epinut,
Thanx for the input. This helps alot. Due to the lack of a true K shop manual, this board turns out to be the best tech source.
Cody

Dick,

To add a bit of information to the subject of how fast a K model was (is) I offer the following excerpt from an article I found on the i-net a few months back, from a forthcoming book by Erik Hoopes titled “The Model K Harley Davidson Motorcycle”. This article also contained the following request – “Erik invites all K owners to contribute any K pictures, with a short story, for the K Book. For more information contact Erik at ekhi156@gci.net or by phone at 07-456-1561”.

The specific passage below is taken from the 1954 model year description. I think it is pretty impressive that the KHK’s may have been very similar in performance to the 1958 XLCH!

“The KH had bigger cams and the KHK had the even larger racing type KK cams. These cams were larger than the ones in Brad Andres` 1955 National Championship KR Motorcycle. The KHKs were hand built factory Hot Rods that also benefited from extensive additional port work and head machining. The headwork increased flow and made room for the valves necessary due to the high-lift cams. Valve springs were changed to the KR racer type. A new Linkert M-53A1 carburetor was added to the package. All this translated into a motorcycle that now produced 38 Horsepower and 1/4 mile dragstrip times were over two seconds quicker than the standard K. The KH would now do the 1/4 in 14.75 seconds. I don`t have performance figures for the KHK but obviously they would be even better.

Now I would like to point out that several books often portray the K as being a sub-standard motorcycle, (in the power department), and not really even being acceptable until it received Overhead Valves and was called an XL. However a 1966 XLH took 15.5 seconds to do the 1/4, although a 1958 XLCH would run it in 14.25. The first Sportster in 1957 had only 7.5 to 1 compression and 40 Horsepower, then the 1958 was upgraded to 9 to 1 with bigger valves. Also the 58 XLCH was a lightweight stripped down motorcycle. No battery, etc. The point I`m making is that granted, the first year K was no rocket at 16.8 seconds but all the other ones, KK, KH, and KHK Models were quite fast motorcycles. Even with its` battery, full fenders, large FL type headlight, huge gas tank and full tins the KH was only a half a second slower than the XLCH. I wonder what numbers the KHK would produce? I feel the K`s deserve a lot more recognition for performance than they ever normally receive.”

Hi All,

I have always assumed, rightly or wrongly, no proof as such, that KK and KHK cams were just 1st year KR cams... As Brad Andres' KR was the one with Sifton homemade/stroboscope developped KR cams, they might well have been less "timed" than std KR, but they surely worked better!!! That same KR brought #1 plates to Joe Leonard and Brad 2 years on the trot!!!

Nice to ear Erik's still working on his book up there in Alaska, he must have had my contributions for the best part of 10 years!!!

All I can say about KHK performance/torque is to tell you that mine's pulling this quite high ratio to keep the revs down and still will do 95mph any day: 34 x 59 primary, 20 x 44 secondary.............

Patrick

[Pa]

I lost a State Police car [ a Chrysler 440 ] on my first 55KHK. The road was a flat out straight away for a good 5 miles. He didn't even get close to me. Last I saw of him in my mirror, he was more like a speck of fly doo doo in my mirror. Yeah Buddy !! That bike would fly !! Pa

Lets be real here. I like KHK's And have built and rode both KHK's and XLCH's. There is no comparison in power. A CH will put the hurts on a KHK stock for stock. Anything else is wishfull thinking.

I agree with you, hotrods1, but I do like the way the KHK delivers its power, none of the CH "hitting the cam" around 4000rpm, sort of good pushing all the way through the revs!!!

Patrick

Other than these markings on my cylinders, there's nothing else on the base...These are KH cylinders.

How does one date them?

Any there is not a hole in the cylinder for any oiler.

George

Looks like they are 54 casting numbers. Hard to read the last digit, but my 55 KH cylinders have 16581-54 casting numbers. My KH/Early Sportster Spare Parts Catalog only lists a 54 part number for the KH cylinder.

Hi,
mine are REAR 16581-54 AND the FRONT is 16561-54???

Any ideas? Best, Nick.

Nick,

Front and rear cylinders would have different casting numbers and part numbers. Just checked my 55 KH again. It has the same front and rear casting numbers as yours.

Finally getting around to messing about with my cylinders for the engine build.

I did clean up the cylinders a bit and found the oiler holes.

Question,

Good way to remove the screws in the cylinder base??? Sure are tight and I don't want to break anything

Thanks

George