1920 Harley Model F

[TechNoir]

Hi Cotton,

I really appreciate the work that you have put into understanding these old carbs and the advice that you have provided during this project.

John

[T. Cotten]

Its not something you can observe easily, John,..

If at all, in order to set the float without a mess. Did you notice how the fluid in the bowl wants to leap up to a caliper 'tail'? Even my sight glass tubing was subject to surface tension issues, even with spirits.

It was tedious research for me to nail down this otherwise useless fact, but necessary to produce proper floats of various models. Once we knew the fuel level original floats produced, then the modern material could be made to produce the same, at book spec,.. avoiding confusions.

The Ducky buoyancy is virtually identical to the OEM "Armstrong" productions.
And a little bit more resistant to modern fuels.
Good luck.

....Cotten

[TechNoir]

Cotton,

Thanks, knowing the fuel level is the key piece of information. I will set the float level with the bowl and see where the fuel lies.

Thanks also for the picture, I always hugely appreciate your advice and also you sharing your tools and techniques.

John.

[T. Cotten]

The resulting fuel level should be about 5/8", John!

Others have corroborated that finding; L&L spec'd the same setting to produce this level for both cork and their 'Armstrong' floats, although the floatlevers/pivotnuts were altered to accommodate the change.

It proved to be much the same fuel level for DLXs.

SITGLS13.jpg

The FB crowd must be as ignorant of my floats as I am of them. (That's okay, it can stay that way.)

....Cotten
PS: Please note in your third pic with the floatvalve on the 'correct' side, the drain plug to the bowl is centered to empty completely when the machine is leaned left.

[TechNoir]

The offset for the float in Linkert manuals assumes the floatvalve is under the 'Power' needle, on the opposite side of the carb, in order to clear the eccentric bowlstem boss..

Thanks for the information Cotton. I had already thought that this might be the case which is why I asked on the fb group.

There are certainly people on that group who have mounted the bowl the "wrong" way with no problems. Unfortunately for me I also want to mount my carb the "wrong" way too.

I will wait until the new float arrives and experiment with positions some more.

Please note that the float should be level in the bowl when the valve closes, and more critical than an "exact" quarter-inch. And you will need a proper pivotnut/screw.

Again, great info. I had wondered what the correct fuel level should be as opposed to float level because the fuel level will differ according to the density of the float material.

I have ordered a new nut/screw along with the float from Holland.


One of those spacers would certainly have saved me some time, never mind I have made one now.


"PS: What "Linkert group"?"

I am on two facebook groups (thanks to Steve Swan) relating to Linkerts or Scheblers.

The first is "The Linkert "M" Series Carburettor Discussion Group". Link here: https://www.facebook.com/groups/1906782259651628

The second is "Schebler/Linkert Carb Hunters". Link here: https://www.facebook.com/groups/649635005210815

They are closed groups so you have to ask to join but that's just to prevent the usual facebook crap from polluting them.

Thanks again.

John

[T. Cotten]

Your bowl is not indexed properly, John!

(In the first two pics, anyway.)

The offset for the float in Linkert manuals assumes the floatvalve is under the 'Power' needle, on the opposite side of the carb, in order to clear the eccentric bowlstem boss.
The only way to inspect for clearance between the float and the bowlstem is to flip the entire carb and bowl upside down, and suck upon the valve.
Once indexed, please leave it there.

A Rubber Ducky will certainly be better than the boatanchor you have! (But beware they are not immune to some of today's fuels.)
Please note that the float should be level in the bowl when the valve closes, and more critical than an "exact" quarter-inch. And you will need a proper pivotnut/screw.

....Cotten
PS: What "Linkert group"?
PPS: One of these common spacers may have saved you a lot of time....
INLETEXT.jpg
.

[TechNoir]

However I need to get it to fit properly. I could make a longer spacer and fit it in the front position but that is ruled out for several reasons. I did also ponder making a new oil pipe but I also posted some queries on the Linkert M Series fb group. They confirmed that it shouldn't leak in either position. So I spent some time checking things out and established that:

1. the float valve is fine (see picture below)
2. the float seems to not have enough clearance between the inner face of the doughnut and the carburetor.


Build 435.jpg


The Linkert group all recommend "Rubber Ducky" floats for these carbs and looking at the pictures of these floats online it has a distinctly different cross section to the one that I have. Mine has parallel inner and outer sides of the doughnut but the Rubber Ducky has a vertical outer face and an angled inner face. The angled inner face will give much more clearance between the float and carb.

That was a couple of days before Christmas so I have ordered a new Rubber Ducky float from 45parts in Holland but I think they are currently shut for the holidays so I am not sure when it will arrive.

So that's where things are right now. Once the float arrives it should be a simple job to get it finished.

I will update once I have the float.


John

[TechNoir]

The Linkert needs a spacer to make it fit and I estimated that it needed a 1/2" spacer. So I made one and also longer screws and mounted the carb, all seemed fine. However I had also decided to fit a Linkert fuel filter because I had dispensed with the in-tank filtration when I lined my left tank. At this point I realised that there wasn't enough clearance between the carb and the cylinder to fit the filter using the 1/2" spacer so i had to make a 1" spacer and even longer screws.

Once that was done, all was good. I made a new copper fuel pipe to suit the new arrangement and connected everything together, also the Schebler throttle sleeve fitted with just some minor adjustments.


Build 431.jpg


Build 432.jpg


Build 433.jpg


Build 434.jpg


Build 436.jpg


I drained the sump and refilled it and then filled the left tank with fuel and turned on the tap and then watched fuel pour out of the top of the float bowl.

I had the float bowl off and on loads of times and checked everything and it was fine with the outlet to the front of the air intake and it leaks with it to the rear of the air intake. I need to mount the fuel inlet to the rear of the air intake because the original oil pipe obstructs the fuel filter when it is in the forward position.

At this point I decided that wanted to see how/if the Linkert worked so I dispensed with the filter and fitted the fuel inlet in the forward position where it didn't flood. Then I used a rubber hose and two clamps to get fuel to the carb. The bike would not start after a few kicks but I noticed that the air intake was quite wet with fuel so I opened the choke and a few more kicks and it started. It idles OK enough given that its not been adjusted at all and I am happy with it. It will be better with a properly warmed up engine and proper adjustment. I was now happy with the decision to swap to the Linkert so I can ride it.

John

[TechNoir]

It should work fine, John!

With the DLX support I mentioned previously.

....Cotten

Thanks Cotton. I did buy a repop one from CD. I will sort out the support once I have everything else fitted.

John

[T. Cotten]

It should work fine, John!

With the DLX support I mentioned previously.

....Cotten

[TechNoir]

At this point I decided that I needed to get the bike running and the Schebler was an on-going issue. Sure it runs but it does so terribly. I have tried every adjustment and check I can think of or that has been suggested on here and elsewhere.

However I do know that it will run much better with a different carb so i did some research (note: by this time my AMCA membershp had lapsed which is why I didnt ask on here). I found Eric Smith's thread about his 1916 on the CAIMAG forum before it shut down. Also, following recommendations from Steve Swan, I joined the Linkert M Series Facebook group and the Harley J/JD Facebook group and spoke to the guys on those groups. Following that I weighed up my options and sourced a Linkert M-18. For reasons too long to explain I didn't get my hands on the Linkert until early December.

I also sourced some other parts to make new fuel lines and also an intake bell, a huge thanks to Steve Swan who acted as a logistics hub for me in the USA.


Build 428.jpg


Here is the gap where the carb will be fitted, I have included this picture to point out the original oil line that you can see passing down the front cylinder and then across to the other side of the bike for reference to later.


Build 430.jpg


John

[TechNoir]

Hi Cotton, thanks, as always, for your input. My original cam strip has been plated and only a bit of metal is showing which is why I mistook it for copper.

I did the sucking on the stem thing numerous times to get the idle position and have adjusted both ends of the strip dozens of times. I want to ride this bike a bit so I am making an alternative arrangement for now, see my next post.

Hi Mike, thanks for the comments.

John

[ihrescue]

Good to see you are back and working on the old bike again. You may recall I did a summary article on your build thread for the AMCA Newsletter with the intent to entice interest in the member bike build threads and the forum. It was the first of a few articles I wrote to send in the Welcome email I send to new forum members. I feel if we can get people interested in one of these threads and all the side projects, problem solving and helpful solutions that fellow members offer then they can see one of the many values of the AMCA Community Forum.

Good luck and progress

Mike Love

[T. Cotten]

The cam strips were beryllium spring alloy, John!

Hard brass works, so I'm sure stainless could too, but I would fear the wheel would just slip, instead of roll.
(Some later models just had a little Micarta finger that was intended to slip.)

With the carb in hand and the bowl removed, first make certain that at idle position, the needle can fully shut the seat, by sucking upon the nozzle tube where it is soldered and ground away on the bowlstem. Then, as you back the needle out a turn or so, you should sense if you are drawing fuel to run, and then open the throttle gradually for a feel of how the cam is proportionally opening the needle further for higher speeds.

Fine-tuning the screws on either end of the cam (some have none, and some have two and no dial) is something I've never had the opportunity to play with.

Happy Holidays!

....Cotten
PS: Is that where you have the bowl indexed when running?

[TechNoir]

Next job was to make a jig so I could bend the new cam strip into the right shape.


Build 426.jpg


Reassembly was the reverse procedure and was pretty straightforward.

I have read somewhere else that an alternative to the cam wheel is a fixed PTFE wheel. I don't know if its a good long term solution but I figure that using a fixed wheel would eliminate any wobble or irregularity in a proper wheel so it would be a good starting point to test the new cam strip. So I made a PTFE wheel and screwed that on.


Build 427.jpg


All of this made absolutely no difference to the carb no matter how I tried adjusting it.

John