Heads Up – K Model Head Quandary?

Production K Models

Re: Heads Up – K Model Head Quandary?

Postby thefrenchowl » Mon Jun 26, 2017 8:10 am

wz507,

You have all my blessings in your holly grail search for improved flow from what the factory, Jerry Branch, Axtell, Len Andres and a few others achieved in 17 years of trying while discarding hundred of fooked heads and fooked barrels...

It's like trying 500 years from Galileo to prove to yourself that indeed, the earth is not the centre of the universe. The same ground has been covered umpteen times since

WHY????

Get a 1969 race instruction booklet and follow the #7 head drawings for the various carvings, not forgetting the cylinders as well, loads more work there than on the blinking heads.

Patrick
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Re: Heads Up – K Model Head Quandary?

Postby wz507 » Mon Jun 26, 2017 9:58 am

thefrenchowl wrote:wz507,

You have all my blessings in your holly grail search for improved flow from what the factory, Jerry Branch, Axtell, Len Andres and a few others achieved in 17 years of trying while discarding hundred of fooked heads and fooked barrels...

It's like trying 500 years from Galileo to prove to yourself that indeed, the earth is not the centre of the universe. The same ground has been covered umpteen times since

WHY????

Get a 1969 race instruction booklet and follow the #7 head drawings for the various carvings, not forgetting the cylinders as well, loads more work there than on the blinking heads.

Patrick

Patrick,

Evidently you saw the word “airflow” and jumped to the incorrect conclusion that some holy grail airflow pilgrimage was underway, which could not be further from the truth.

I have no KR valves or cylinders or heads. I am a hobbyist with access to a flow bench. I am building a nearly stock 56 KHK. I have 3 heads at my disposal - a stock K, a machine spotted head (KK?) and a fully machine KHK head. After new valve seats are installed in the cylinder and a valve job is done I simply want to put the different heads on the cylinder and quantify airflow to see if the different heads flow differently. I already know the port is large relative to OHV applications and therefore port speed should be relatively low. But that evidently is what works on the K engine design.

Since I have the -52R combustion chamber casting, thought I’d use this to make an epoxy head with the early R combustion chamber to compare this head with the other 3, which is much easier than trying to sculpt it from a stock chamber casting.

Regarding your question “WHY?” For all the reasons above and simply because I’m curious and have never seen a single airflow volume or port speed number published for any K engine (K or KR), so if doing it myself is the only way to see the numbers, then why not? If you or anybody has such information and could direct me to that information source I’d be grateful.

Regarding the 1969 instruction booklet, is the information there different or more in-depth than the circa 1959 Competition Racer manual that shows the #7 head drawings with shelf location and valve to head clearance?
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Re: Heads Up – K Model Head Quandary?

Postby thefrenchowl » Mon Jun 26, 2017 10:48 am

Hi Kurt,

It just that sometimes, I feel guys would be better off wrenching/on the road rather than dwelling in theories that have been exhausted since decades!!!

My bikes always went like the clappers without too much analysis, just a good old fashionned sense of mechanics vs stresses and aesthetics and how far/little could I get away with in terms of reliability in my constant battle between ""ideal world"" and lack of funds/use old parts...

Whatever you do or fit on your 56 KHK won't make a iota's difference on the way it runs since you'll only run it at 5500rpm if you're sensible and all the mods/variants will have their full effects felt at 7500rpm. Cam timing is the answer here for a street bike... And the KK/KHK cam has plenty of go.

That's said, I don't have any flow data either for K, KH or KR heads/cyls, and if you do it, you'll probably be very surprised as they will all be on the very lowly side.

What O Brien and the rest discovered was that flow inlet/exhaust speeds in side valves are best ignored and one should concentrate on doing whatever will work to help the puny flow turn 180 degrees to fill/exhaust the cylinders. Hence biggish valves compared to OHV, wild acc and decc ramps on cams, 30 degrees seats, very flat valves, channels etc...

My OEM (Not reprints...) 58 and 64 race instruction manuals have no head or cylinder drawings, so I guess you have a "mix and match" repro set. The #7 heads and barrels drg were only published in the 69 manual along the dome pistons drgs.

On the dome subject since you've asked, in 2 years of running them HD and cohort had problems. Problems like they had in 52 when the KR came out, but from 52 till 69, they had plenty of time to iron everything bad out...

Since 68/69 was the last of the Mohicans, HD did not spend too much time on these domes, what with 200 iron XRs to design and build, change of rules and the rest. So, unfinished business.

Nothing to say that it would not have worked if 17 more years of mixed rule had followed, who knows???

But from a personnal point of view, I still feel the dome was dead before it started due to the lack of shelf angle that plays a very critical part in 180ed the flow...

And I've said it before here, no use talking just about heads, the K is a mix of head and cyl work, it won't give its best by looking at just one of the two.

Patrick
Flat Head Forever
https://web.archive.org/web/20071011184353/http://www.harleykrxlrtt.com/index.htm
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Re: Heads Up – K Model Head Quandary?

Postby ambike » Tue Jun 27, 2017 4:23 pm

" Valve timing and carburetion, everything else takes care of itself. "
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Re: Heads Up – K Model Head Quandary?

Postby LDB » Tue Jun 27, 2017 5:07 pm

Mr. Patrick

In your post above, what do you mean by "in 180ed the flow..." when referring to the shelf angle?

Thanks
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Re: Heads Up – K Model Head Quandary?

Postby thefrenchowl » Tue Jun 27, 2017 5:17 pm

Inlet flow goes up vertically in inlet track, hits the valve, turns 90 degrees to horizontal, hits the shelf, goes 90 degrees down the cylinder.

Same in reverse for exhaust flow.

Patrick
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Re: Heads Up – K Model Head Quandary?

Postby wz507 » Wed Aug 09, 2017 11:20 pm

Revisiting the subject of how many K model head variants exist, we have so far seen several variants in castings and several variants in combustion chamber machining. I’d like to revisit the latter of these subjects, i.e., the combustion chamber variants. I have personally seen 3 general classes of combustion chamber; 1) the "as-cast" chamber, 2) the chamber that is simply “spotted” over each valve to provide minimal relief or alteration to the chamber, and lastly, the more "fully machined" chamber where it appears to be fly-cut perpendicular to the gasket surface all the way to the top of the head and ends in a square edge. For clarity sake an image of each chamber is provided below.

My primary question at this time is, “on what models were the various chambers used?”. From measuring I’ve done it appears that both the “spotted” and “fully machined” chambers would work with all models whereas with the as-cast chamber there might be a slight chance that a 1.812” IN valve might contact the roof of the chamber on the slanted roof transition between the IN and EX valves. However the “as cast” head I measured earlier in this thread to determine maximum allowable lift provided valve lift of greater than 0.425” inch which is plenty of clearance for any K model cam made for consumer bikes. Of course this was on my cylinder and I can't say if my valve seat height is representative or not.

Anyway, interested to hear opinions as to where the 3 chambers shown here were used, as well as if others have seen chambers not shown here and where they might have been used. Thank you.

“as-cast” chamber (L), “spotted” chamber (C), “fully machined” chamber (R)

LR 3 different combustion chambers.jpg
LR 3 different combustion chambers.jpg (69.12 KiB) Viewed 13609 times
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Re: Heads Up – K Model Head Quandary?

Postby wz507 » Wed Aug 09, 2017 11:54 pm

Recently acquired a very nice late K model head that had a peculiar and unexplained anomaly that I thought worth passing along. The subject head is a late casting with the encircled E beneath the casting number, a short window between upper and lower fins, full length fins encircling the spark plug hole and a “spotted” combustion chamber. Now for the weird thing. After dusting it off with the bead blaster I was inspecting it for cracks, flaws, or whatever, and as I glanced at the top of the head and surveyed the fin pattern my eye was drawn to the area between the 1st and 2nd fin on the right side of the head, i.e., the area where a KR casting number would normally be present if it was a KR head, which it isn’t. However, upon closer inspection it was clear that someone had been in there with a burr grinding out something that shouldn’t have been there – a casting flaw, an inappropriate R number? Since the grinding marks just happen to be the correct length and at exactly the 2 locations that an “R” casting number would be I can’t imagine any scenario other than that the head was inadvertently cast with an “R” number present and after finding out that a mistake had been made it was a quick fix to simply remove the casting number on the heads made like this, change the mold to the correct top with no “R” number, and get on with making the order.

What do you think? Thank you.

LR reworked spotted late style head.jpg
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Re: Heads Up – K Model Head Quandary?

Postby EKHKHK56 » Thu Aug 10, 2017 4:29 pm

The best KR shape in my opinion was the basic one with the ice cream cone shape made in 1952. This was the workhorse design that got it done. Standard flat top piston with cylinder relieving and some head relieving if needed to keep compression down to under 6. As in 5.99 FLOW is more important than COMPRESSION in this type engine. Good enough for Brad Andres to break the beach tape @126mph at Daytona 1956. Erik K
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Re: Heads Up – K Model Head Quandary?

Postby Coolbreeze » Sat Jan 05, 2019 2:24 am

Patrick,

On 28 April 2017, you posted a couple of photos in this thread showing, inter alia, your front brake. Those photos no longer will open. Would you mind re-posting them?
I am considering replacing the reliable steel front hub/drum on my '56 KHK with the more delicate aluminum full width brake setup from a mid- to late-60s Sportster. I have looked with no success for a thread addressing this modification.

George
'56 KHK
'60 XLCH
'48 Chief
'42 Indian 841
'64 BMW R69S
'84 Moto Guzzi V65Sp
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