Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models KR top + KHK bottom = stroker plate

KR top + KHK bottom = stroker plate

Post Wed Aug 27, 2008 1:14 pm

Posts: 13
Can anyone give me info on the spacer that is required for the use of KR cylinders on a KHK flywheel? I understand what it is any why it is. I'm interested in what the best material is to use and who has had what success with which set-up.

For instance, I could stack a bunch of base gaskets up, cut a piece of aluminum stock and sand it down to the right thickness, saw off the bottom of a fowled set of cylinders, buy a set on ebay, beg patrick for a set of cast-offs, draw up specs and have a machine shop cut them out of cylinder stock... or I could go for a 750cc set up with an XL flywheel.

Any insight would be greatfully appreciated.

Post Wed Aug 27, 2008 2:03 pm

Posts: 13
richie, you idiot, measure the difference in stroke and divide by two. find a sheet of aluminum stock that is just under your measurement and use a base gasket to cut out a spacer. coat each side of the spacer with an aluminum based liquid gaset. and assemble. you should get a slight pop-up on the piston but watch out for piston to head clearance, and if you can, check your compression ratio. done and done.

Post Wed Aug 27, 2008 2:53 pm

Posts: 591
Location: Crewe, Great Britain

Yep, you've got it in 1!!! Required spacers are about 8mm...

Or find a set of KHR cylinders!!!


Post Thu Aug 28, 2008 4:54 pm

Last edited by panic on Sat Aug 30, 2008 8:06 am, edited 1 time in total.

Post Fri Aug 29, 2008 12:57 am

Posts: 591
Location: Crewe, Great Britain

Hi Panic,

No, manifold's the same, brass nipples just slide out a bit more, and tappet screws/covers the same. K and KH valves are the same lenght but not quite the same diameter: KH inlet a bit bigger, KH exhaust a bit smaller.


Post Fri Aug 29, 2008 7:45 am

Posts: 13
Patrick and Panic,

Thank you both for your advice.

I was hoping to adjust compression with the spacer plate for something peppy but still easy to start and adjusted to modern feul octane. I've read of the pop-up piston which I have never seen but seems to have an adjusted crown height. I was hoping to get the same effect with the adjustment of the cylinder by way of the plate. I would like to go without gaskets and just dress the mating surfaces well and use the liquid gasket material. Plan B would be to use two gaskets and a different plate thickness. I would be interested if anyone has run either or both with success.

my intake manifold is a dual tilly. I'm using KR cylinders which have not been modified for this set-up. The recommended solution is to braze in a nipple that is the correct clearance. I would like to use the existing plumbers hardware and not modify the cylinders at all. Best left in tact. So the intake solution will be a bit custom anyway.

I'm using a dual valve spring set-up, innies and outies. I've been told that the tappets will adjust out to meet the new deck height (which should be a bit less than KHK). I am not wild about this as it leaves less thread covered on the adjuster screw, when I perfer to have more coverage. I may search for a substitute adjusting screw from a U or W or something, but I think what I have will work. (moment of prayer) I just thought of using the bucket and shim from a ducati I wonder...

I think the covers will fit with the same caveat as the tappets. I an not as concerned about having less coverage here because it is a non-stressed part and it is always nicer to have more space for doing the adjustments. The only thing I am not sure of is the cover fit over the dual spring seats which is a two teir arraingement made from aluminum.

when i think of all of the details that need to be sorted my head swims. I have all the time in the world for it, but ache to rid eit. Thankfully I have my trusty shovelhead to ride in the interim.

Thank you both, sorry for any poor spelling, i can't find the spell check and have become a slave to it.


Post Fri Aug 29, 2008 10:50 am

Posts: 591
Location: Crewe, Great Britain

Hi richie55KHK,

Twin Tillotson à la KR for the street, good luck!!!, it's next to impossible to tune them to get proper iddle and transition with the diaphragm vertical. I know, I did try it on my KHK some years back. I then spayed the manifold so I could mount them the Sportster way, they worked OK then.

The factory cast alloy twin manifold: It's also designed to fit only the moded cylinders, inlet track shortened by about 1/4", then no threads left, that's why the nipples are brazed in, then machined internally...

That's how I've done it so as not to cut my KHK cylinders: Special threaded nipples and dead thin manifold. The entry curve is then tighter than the factory one.


Don't worry about the lenght of the std tappet screws, I've never had problems with them.

You will need a extra collar to screw on the K/KH tappet block thread to fit the lower KR valve collar.

All the best from Patrick

Post Sun Aug 31, 2008 8:15 am

Re "manifold's the same" (not too short):

Easy way to tell when the manifold is too short: every time the cylinders are raised.

Did you mean "the manifold is too short, but the difference is small enough that it doesn't pose a serious problem?"

How to tell with any H-D twin engine (except V-Rod):

Let H = cylinder height change (added or subtracted)
Let W = manifold width error (can be positive or negative) - this is across the legs end-to-end

W = H × .76537 (just use 3/4, it's easier and 98% accurate)

Example, using the K/KH problem:
H = +.375"
W = .287"

The manifold is slightly more than 9/32" too short.

On 1930-32 V, 1929-35 D/R and 1936-65 OHV with T manifolds, this is also the exact leg error (divide by 2 for the correction to each leg to keep the carburetor flange centered if it's good now).

On 1933-48 V/U, 1936-73 45, 1952-* K/KH/KR the individual leg length error is greater.
Each leg is too short by .5412 × H.
H = +.375"
W = .203"

On 1957-* iron Sportster, 1966-* big twin, and all Indian twins with Y manifolds the individual leg length error is different.
Each leg is too short by .4419 × H.
H = +.375"
W = .166"
Last edited by panic on Sun Aug 31, 2008 8:45 am, edited 2 times in total.

Post Sun Aug 31, 2008 8:27 am

Posts: 591
Location: Crewe, Great Britain


I just meant the factory used the same old manifold, nuts, olives and nipples, all -40 # except nipples which are -48 # on K and KH, some WR and most KR, so there must have been some leeway all along.

Still, knowing the propency for H-D to mod parts without changing the #, I can't vouch for everything, i.e. cast brass versus cast iron 4 holes manifolds...


Post Sun Aug 31, 2008 10:39 am

What's missing: the KH cylinder castings have the female nipple threads moved out-board (towards each other) to compensate for the extra width.

Post Sun Aug 31, 2008 10:45 am

Posts: 591
Location: Crewe, Great Britain

Could be, Panic, but I haven't got any K cyls to compare to my few KH ones.

But I have a KR cyl, I'll have to check!!!


Post Sun Aug 31, 2008 11:02 am

Posts: 591
Location: Crewe, Great Britain

Yes, Panic!!!

You're right again, KH on left, KR on right:



Post Sun Aug 31, 2008 2:50 pm

Found that out when I bought a KH with 1 KH barrel and 1 K barrel and a stroker plate...

Post Fri Sep 05, 2008 1:45 pm

Posts: 13
That is all I've heard about the dual tilly set-up. Bad, bad, bad.

I'm working with a guy who likes all the cool stuff, but I just want to get a runner, for cheap.

There is this big deal about Kosman disc wheels. I was lacing up the back one and found three nipples missing. They are the stainless ones that fit the thick spokes but go into the small rim holes. So I'm looking all over the shop through boxes of nipples looking for three matches. Yikes, I just grabbed two nice older wheels in the last 10 minutes, and split. done and done. I just need them for mock-up anyway. If I can figure out how to make the Kosmans work later, then I'll swap them out.

I feel the same with the dual carbs. cool stuff, but what I REALLY like about harley is it is stone simple. one carb, two jugs, and go. And if I can figure out how to make the tilly's work...then I'll have to sync them all the time...crap!

The K is actually not what I was looking for. I went in looking for an iron XL and wanted to set it up with just the front cylinder, seal the trap door, open narrow belt primary, magneto, battery-less lighting, no kick, la mons start, 19" front and rear. And for God sake, a quiet muffler. like the silent grey fellow. That bike is still in my head. I wish the voices would stop. I like the cases on that engine when you cut everything off that you don't need with the above description. I know, cutting a case is blasphemy, but he has a bunch of blown out crap, with no matching numbers, that's cut a little anyway. a little welding and cutting and I'll have what I want without the guilt. What had been garbage is now my ride. beauty and peace.

I'm not sure I fit in this forum. Thanks for the info tho, very helpfull on many levels. and I do have the KR cylinders with the longer manifold threads.


Post Fri Sep 05, 2008 3:11 pm

Posts: 591
Location: Crewe, Great Britain

Don't go away, Richie,

I DO like specials and don't mind cutting things off meself!!! I like the old stuff both original or moded and think the H-D are well designed to cope with mods.

I wasn't trying to deter you from trying the twin Tillies route, just a bit of warning it won't be plain sailing!!!

I went the cut down XLCH route as well, my 67 one:



Worked fine until the front Dytch cylinder parted with its base!!!


Post Sat Sep 06, 2008 12:49 am

Posts: 1654
I agree with Patrick. there are some VERY non-standard bikes on here and the builders as well; some of them are completely non-stock, except they tend to be assemblies of modded H-D parts, rather than xeroxed from the Zodiac or Ness catalogues.

your bike seems to fit right in, to me.

it's true that if you ask a question for which the answer is 'don't do that, it doesn't work' then you will get that as a reply, but isn't that why you asked the question?
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sat Sep 06, 2008 9:48 pm

Posts: 1676
Location: Interlaken, NY USA

Patrick, That's got to be one of the neatest looking sportsters I've seen. It just really catches my eye. Nice job.

Post Sun Sep 07, 2008 8:16 pm

Posts: 13
ok, i'm back on track. allot of folks tell me i shouldn't do stuff cause it is just stupid. and it is stupid. i want to do the same thing with my shovelhead FLT, take off most of the non-essentials, add a magneto, drop the battery, battery, no electric start...well bump that shit! but i really think trying to bump start my 600 lb flt every day at work is stupid, but i can't stop thinking about it. if it is in tune it'll go.

Patrick, nice. dual plug, battery under tail?, i love the up-pipe, i want that for the iron one cylinder bike, but on the old frame bolted to the rear fender stay, love the swiss cheese and primary treatment, although i'd like to go way open on the primary, pant legs be damned, is that an XR frame with the bottom loops cut, yikes! i've thought about that since i saw the bmw cafe like that, but i'm worried about the torsion on the front mounts, cerriani's? love the low sump on the gas tank and shovelhead oil cap motif, and the cheezy chinese horn, oh Patrick, fiamm hi/lo duals direct off the battery with a relay, autozone US$30.

The thing about the FLT is the frame, it's lovely the way it juts out in front with the reverse triple tree. and the engine hangs a la buell. so you can cut the bottom rails without worry of torsional stress. and the motor takes a morris mag (morristown, nj) and the motor would be lovely with the primary case flanges cut off the crankcase and trany, and a skinny belt, and you just bump that shit every day at work, and the nay sayers can go quack with the ducks.

thank you all, you are the best!

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