Carburetors, Linkerts used on all K Models

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Carburetors, Linkerts used on all K Models

Postby Cave's OSC » Sun Apr 11, 2021 8:00 am

Hello JerrryR. Thanks for the picture of the M53A. It is the first one I've ever seen. I own a M53, complete with manifold and air cleaner. A M53A1 missing the backing plate and bracket for the air cleaner cover. If you are interested in selling your M53A - you have a serious buyer here. Also if you see one for sale, just the body or complete please inform me. And of course the M53A1 backing plate p/n 29020-56 and/or the bracket p/n 29049-56. I also Have MR4, none are for sale. I restore Linkert's for HD's only. And have refurbished some. But mostly I restore carbs to NOS condition, museum quality. No coatings, plating, or parts that weren't originally on them, and they operate. I'm interested in any source or resource about the Brass Linkerts use exclusively on HD's from 1930 to 1965, both to receive and to share. Cave PS haven't been able to send files? contact me at [email protected]
Last edited by Cave's OSC on Mon Apr 12, 2021 9:06 am, edited 1 time in total.
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Re: Carburetors, Linkerts used on all K Models

Postby panic » Sun Apr 11, 2021 2:10 pm

Never mind
Last edited by panic on Sun Apr 11, 2021 6:30 pm, edited 1 time in total.
[url="http://victorylibrary.com/L-BK.htm"]The Linkert Book[/url]
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Re: Carburetors, Linkerts used on all K Models

Postby Cave's OSC » Sun Apr 11, 2021 4:37 pm

Hello Panic. I'm A little confused about your replay?

The Linkert M53 and the M53A1 were used only on K, KH and K variants only. These two carbs were four bolt intake manifold intake to carb. And only used on K's.
K's 1952 to 1956. These years also only used Linkert carbs.

The MR4, MR4A,MR5, were all four bolt intake manifold to carb. And were all Harley racing carbs. All are 4 bolt intake manifold to carb. (I can't or haven't yet located documents on what Harley-Davidson's these three M model Linkert's were mounted on. The MR4 was possibly used on K models used in racing?

K model flat head side valve engines used a four bolt intake manifold to carb. the air cleaners were left side, as all HD side valves engines.

I'm not following your 1940 thought pattern here?

Do you have any materials, catalog, service manuals that list the M53A? Or better yet do you know of one for sale?
Thank You for your help and knowledge.
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Re: Carburetors, Linkerts used on all K Models

Postby ChillyWilly » Sun Apr 11, 2021 5:25 pm

I find that Linkerts are a rather deep subject. One good reference is The Linkert Book which covers many aspects of application, operation and refinement of this carb. While Palmer only touches on anything to do with K and XL lines when it suits him, the carb section of the current 2 volume set has some very good charts on sizes of jets and other configuration issues which you might find handy some day. I bought a rebuilt M53A1 for my 54KH from Linkert Carbs (ITW Trading) when I obtained the Collection of Parts that is now my rider K model. The parts that came with my project included a core M53. At the time I was unable to rebuild it due to lack of choke shaft which is a scarce part then and now. Still on my wish list. I have bought a brass bombsight venturi as it is supposed to provide a smoother response than the standard one. It proved a failure as the main nozzle that I have only reaches to the bottom of the central venturi instead of the center of the bore. This produces a horrible flat spot off idle. Anyone suggesting a source of the proper part would find a huge thanks from me..
Any question that I can answer, please feel free to ask..no sense all of us learning the hard way.
To bring a bit of the past back to life seems a good thing...
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Re: Carburetors, Linkerts used on all K Models

Postby wz507 » Sun Apr 11, 2021 10:26 pm

ChillyWilly wrote: I have bought a brass bombsight venturi as it is supposed to provide a smoother response than the standard one. It proved a failure as the main nozzle that I have only reaches to the bottom of the central venturi instead of the center of the bore. This produces a horrible flat spot off idle. Anyone suggesting a source of the proper part would find a huge thanks from me..
Any question that I can answer, please feel free to ask..no sense all of us learning the hard way.


I believe the sole main nozzle employed in all the Linkert M53 carbs was 27331-52, so if you have that nozzle it should be the proper fitment. The nozzle definitely sits well below bore center in M53A1 carbs, so if you find it below center I would think that is normal height. How does the bike respond when the bombsite venturi is replaced with a conventional venturi?
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Re: Carburetors, Linkerts used on all K Models

Postby JerrryR » Sun Apr 11, 2021 10:51 pm

Hi Caves OSC, I was happy to see you post and start this thread. I've been trying for about the last 10 years to chase down documentation that explicitly states the M53A application. I haven't found much. I bought one at Oley a few years ago and I have seen 2 others. I've attached 3 pictures showing the M53, M53A & the M53A1.
John R from England did a full page write up about these 3 carbs a few years ago, John if your out there can you post it again? Looking forward to seeing what comes of this thread.
JerryR

M53.jpg
M53.jpg (118.64 KiB) Viewed 10197 times


M53A.jpg
M53A.jpg (73.74 KiB) Viewed 10197 times


M53A1.jpg
M53A1.jpg (91.95 KiB) Viewed 10197 times
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Re: Carburetors, Linkerts used on all K Models

Postby Cave's OSC » Mon Apr 12, 2021 9:16 am

Hello ChillyWilly I believe that you can find the information and help on Into the Wilderness Trading site, at www.linkertcarbs.com. Look on that site, the parts you need are under the NOS parts, but look about that site it has a lot of information. I just purchased his last M53, two part K model choke lever from him. Cave'sOSC
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Re: Carburetors, Linkerts used on all K Models

Postby Cave's OSC » Mon Apr 12, 2021 9:18 am

Hello ChillyWilly I believe that you can find the information and help on Into the Wilderness Trading site, at www.linkertcarbs.com. Look on that site, the parts you need are under the NOS parts, but look about that site it has a lot of information. I just purchased his last M53, two part K model choke lever from him. Cave'sOSC
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Re: Carburetors, Linkerts used on all K Models

Postby ChillyWilly » Mon Apr 12, 2021 9:51 pm

I owe answers many:
wz507 re BOMBSIGHT. The performance was awful until I switched back to the conventional 1-5/16 single venturi. It made my old ex-army 45 look quick. Along the way I changed the main jet to a 9 from 8 and changed the throttle disc angle from 8 to 12 degrees. The jet may be too rich now. The disc change made for better transition phase but is more unstable in idle.
A search suggests that the bombsight is a type known as a Dual Venturi. There are also triples and other types. Benefits attributed to the addition of the small venturi include improved atomization, better air/fuel mix over wider range of engine speeds etc. A search of Multiple Venturi Carburation Systems is interesting but sadly I could not download and attach it. The cost of the improvements is said to be a small reduction in power at maximum speeds. What is common is a statement that the main nozzle location should be at the centre of the venturi.
JerryR re M53 picture...can you advise how far up the nozzle extends in your M53 picture? I regret that it is hiding behind the choke. I had felt that the fact that my main nozzle tip only reached the bottom of the small venturi was the reason for my bombsight failure. The main nozzle is aftermarket with an overall length of 1.944 inches. I have no reference to an original early K bombsight and M53 setup. My M53 core is almost completely stripped. The same main nozzle setup seems to work well so far with the single venturi.
Caves OSC re choke shaft. I will certainly try him again. The owmer at Linkert Carbs has previously been unwilling to give up a shaft but if he is out of carbs to rebuild perhaps he will let one go. Glad you have a carb to go forward with.
Cheers All
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