Schebler HX bowl question

[DanM]

I'm rebuilding an HX 181. I have a bowl marked DL4. It is 1.980 overall high. When on the carb body, there is about 1/4 of thread for the bowl nut, which is enough- however to fit a hot air intake it seems insufficient.

The bowl does take the small needle with the ball on it, not the later seat and neelde type

Any advice on the proper bowl for the HX 181? What does the DL4 fit if not this?

And of course- anyone got the proper bowl?

How important is the hot air intake to have?
THX! Dan

[partshunt]

Dan:- I have about 5/16 of thread past the bowl nut. I think my packing seal is inside. Is your seal under the nut or inside? My bowl measure closer to 1.920, a tad shorter than yours. I machined a bit off the bottom of my bowl. (.050" maybe) cuz the plater rounded that area uneven. Also, the bowl nut should only be about 3/16 thick. I havent run my hot air elbow (air bend) so cant say but no problem with the carb in that respect. Maybe its more important if you were in Arizona in summer. As for the part number, There are no part numbers in my 1928 Schebler Book...............Joe

[T. Cotten]

Joe!

Where's Tommo when we need him (as we always do)?

Sorry for this late reply, but I ritually fall into distress from health issues after the Davenport Meet. (Don't ask.)

Another reason to delay was that I hoped that another example of the early 3/4" and 1" H model bowl shown in the attachment would show up on my benches for an accurate measurement.

There is a noticeable difference in height when compared to the 1 1/4"bowl beneath it, and those are prevalent in that they were also applied to bronze DLX's.

And there are two variations (at least) of those as well; I cannot recollect if the DL4 was shorter at the valve than un-marked varieties, as I cannot find my photo record quickly.

I'm certain that the bottom horn is quite important to AMCA judges.

More when I can,


...Cotten

[Tommo]

Sorry Chaps but I didn't initially see this question.
All HX181 carbs I've seen have been on bodies marked H165. I've got 5 on the bench at the moment and they all measure exactly the same.
Stem length (from the top face to the bottom face but not including the bowl nut thread)1 5/8 inches.
Bowl nut thread length 9/16 inch
Bowl nut width 3/16 inch
Bowl depth (Internal measurement top of bowl to the top internal face at the base of the bowl) 1 11/16 inches.
Thats the easy bit. What you have to watch is the condition of the stem thread, especially if an air horn has been fitted for any length of time, as it is generally found that vibration has allowed the air horn to vibrate and wear the bottom few threads it fits on. I've had carbs that people have made bowl nuts to suit the worn thread at the bottom and then tried to force the new bowl nut onto the good threads higher up and wrecked the whole thing.
Now to float bowls. I've seen at least 10 different model H float bowls. The early ones only have a single float pivot screw with the float pivot locating in a small hole in the bowl opposite the screw. These bowls have a cast float arm and the gap the arm passes through is narrower than the later types. We then go to the cast float arm type with 2 float pivot screws, then the ones most will see with the pressed float arm and two pivot screws. There are two different head sizes for the float pivot screws but they all have 1/4 32 TPI threads. Bear in mind that I'm talking about model H float bowls here not just 181 bowls.
When I send a Model H out after overhaul it will have an o ring on the bowl stem internally and a very thin fibre washer under the nut. The washer under the nut is just there to stop the nut damaging the bottom of the bowl when it is tightened and all sealing is done by the o ring. I use an o ring for two reasons one is that it's constant pressure keeps the bowl nut tight without having to use excess pressure on the nut and secondly the o ring makes a far better seal than a fibre washer which takes a long time to size and fit as it's thickness is quite important in this instance.
This all leads to the fact that on HX 180 and HX181 especially you end up with only a few threads to fit an air horn on and I often wonder if Schebler ever intended them to have air horns fitted. Ideally keep everything as thin as possible and you should end up with just enough threads to put the air horn on.
Finally before anyone asks no! I won't overhaul your carb for you. My cobber and I have just finished a batch of 37 Model H's and that is it we've pulled the pin. The carbs we are being asked to overhaul are the ones that 10 years ago were thrown aside as not worth doing anything with and when asked to overhaul this condition carb the cost involved just causes a lot of grief when you present an account at the end.
One little tip, the nut on the top of the throttle shaft that holds the throttle lever on is 5/16 32 TPI and I get asked a lot for them. Find yourself an old motorcycle inner tube and get the nut off there, nice and thin, exactly right for your model H throttle shaft.
Hope this helps.

[Tommo]

Dan
I reread your post.

We leave the air horns off for general riding and only put them on for shows.
They run just fine without them

[T. Cotten]

Whew! At least I was right about the air horn.

Many thanks from all of us Mr T, and please put me at the head of the list for when your book is published!

Honestly,

....Cotten

[Tommo]

Cotton you'll get no books from unless someone else writes it for me.

On fitting model H bowls I thought it might be appropiate to expand a little bit here and explain how I do it.
I don't say this is the right way or the only way but this is how I do it.
I always lap the top bowl surface to its corresponding carb surface and don't fit a gasket there.
This join only stops fuel slops getting out and if the float level is correct the fuel is quite a bit below this join so a lapped surface is just fine and you don't have the hassle of a thin gasket getting all screwed up when you position the bowl to your fuel line.
When you do this procedure you mush ensure a gap remains between the bottom flange on the carb stem and its corresponding surface on the inside at the bottom of the bowl.
What you are aiming at is a gap to give enough nip on the o ring when the nut is tightened sufficiently to get the bowl to nip up on the lapped top surface.
I hope this explains clearly enough how its done and that you can see that a nice soft o ring makes the job a lot easier than quite hard fibre washers which have to be sized to fit.
So many people make the mistake of thinking the seal is made externally between the nut and the bowl and then tighten the nut and mushroom in the bottom of the bowl trying to get it to seal.
Cotton you're a carb man does this make sense to you or is my explaination not clear enough?

[partshunt]

Peter:- Are you saying that HX181 were actually stamped HX165? At least that is how I understand your message here. Am I missing something?.....Joe

Sorry Chaps but I didn't initially see this question.
All HX181 carbs I've seen have been on bodies marked H165. I've got 5 on the bench at the moment and they all measure exactly the same.
Stem length (from the top face to the bottom face but not including the bowl nut thread)1 5/8 inches.
Bowl nut thread length 9/16 inch
Bowl nut width 3/16 inch
Bowl depth (Internal measurement top of bowl to the top internal face at the base of the bowl) 1 11/16 inches.
Thats the easy bit. What you have to watch is the condition of the stem thread, especially if an air horn has been fitted for any length of time, as it is generally found that vibration has allowed the air horn to vibrate and wear the bottom few threads it fits on. I've had carbs that people have made bowl nuts to suit the worn thread at the bottom and then tried to force the new bowl nut onto the good threads higher up and wrecked the whole thing.
Now to float bowls. I've seen at least 10 different model H float bowls. The early ones only have a single float pivot screw with the float pivot locating in a small hole in the bowl opposite the screw. These bowls have a cast float arm and the gap the arm passes through is narrower than the later types. We then go to the cast float arm type with 2 float pivot screws, then the ones most will see with the pressed float arm and two pivot screws. There are two different head sizes for the float pivot screws but they all have 1/4 32 TPI threads. Bear in mind that I'm talking about model H float bowls here not just 181 bowls.
When I send a Model H out after overhaul it will have an o ring on the bowl stem internally and a very thin fibre washer under the nut. The washer under the nut is just there to stop the nut damaging the bottom of the bowl when it is tightened and all sealing is done by the o ring. I use an o ring for two reasons one is that it's constant pressure keeps the bowl nut tight without having to use excess pressure on the nut and secondly the o ring makes a far better seal than a fibre washer which takes a long time to size and fit as it's thickness is quite important in this instance.
This all leads to the fact that on HX 180 and HX181 especially you end up with only a few threads to fit an air horn on and I often wonder if Schebler ever intended them to have air horns fitted. Ideally keep everything as thin as possible and you should end up with just enough threads to put the air horn on.
Finally before anyone asks no! I won't overhaul your carb for you. My cobber and I have just finished a batch of 37 Model H's and that is it we've pulled the pin. The carbs we are being asked to overhaul are the ones that 10 years ago were thrown aside as not worth doing anything with and when asked to overhaul this condition carb the cost involved just causes a lot of grief when you present an account at the end.
One little tip, the nut on the top of the throttle shaft that holds the throttle lever on is 5/16 32 TPI and I get asked a lot for them. Find yourself an old motorcycle inner tube and get the nut off there, nice and thin, exactly right for your model H throttle shaft.
Hope this helps.

[Tommo]

Cotton I thought I'd end up writing a book on this forum when I started on this.
Partshunt; Schebler carbs are all based on a series of standard bodies and are then customised to suit each individual application.
In the case of the HD HX181 and the Indian HX180 they both start out being assembled on a H165 body.
If you look on the stem that the bowl fits over you will find stamped there the body number and in this instance it should be H165.
Sometimes the only difference on the entire carb will be the throttle lever and then, I'm only using numbers here as an example, a HX181 becomes a HX 163 and fits a Thunderbox or whatever if you get my drift.

[partshunt]

Well, the reason I ask is my 1923 JD 74 it has the stamping on top of the body in the usual place "HX165" Would that be correct for that motor as the Schebler book sez HX181 for 1023 74's. Didnt check the stem yet, its on the motor and I wont disturb it at this time....Joe

[Tommo]

Joe,
I've only ever had 1925 and 1928 Schebler handbooks and would dearly love copies of any earlier ones and or any later ones.
The 1925 handbook states on page 22 section 7, Float Heights HX 154 Harley 74 cu in and below that H-- (with no number) Harley 74 cu in with special bowl and horseshoe float yet in the application list on page 29 Harley-Davidson 74 cu in 1921 to 25 HX181.
What we have here is three different carb numbers and perhaps three different carbs all for the same bike.
I suspect the HX165 appeared sometime prior to 1925 but was superseded by the HX181 and that is why the 181 appears in the 1925 application list.
The only way to get an accurate answer is to have access to the Schebler handbooks year by year and try to find where one number first appears and where it is superseded by another number but as I don't have such a resource I can't give you a definative answer.
With regard to the H no number carb mentioned above, I wouldn't mind betting that is the HX165 you're talking about but exactly what the special bowl is I really don't know.
Hell now we're all confused.

[T. Cotten]

Tommo wrote:
"Cotton you'll get no books from unless someone else writes it for me."

Sir, I am an experienced proofer and editor, and would be honored to be at your service!

And your approach to the bottom seals make good sense, however for those of us in the USA, a soft o-ring lasts only a short while in our horribly digestive fuels.
Even cork gaskets impregnated with rubber swell enormously.

Only recently has anyone Stateside stepped up to the plate to produce H model hardware that is superior in quality to one-size-fits-none ebay offerings. Fickau Prototypes has an ever-increasing selection of parts machined with fanatical accuracy.
Fiber washers of varied thickness are on his to-do list, I am certain, but in the meantime every carb remains an individual that must be treated patiently with many one-off repairs.
(Fortunately, I have the material PEEK in surplus for that application, as it can be shaved wafer-thin and easily hidden.)

And the disappearance of Schebler literature is indeed an enigma.
Even '29 to '39 hard-copy seems to have vanished, or is being jealously hoarded.
If we do not re-construct a knowledge base for posterity, who will?

...Cotten

[DanM]

Thanks!

Thanks for all the input. I have the 165 body casting. In the 1928 Schebler manual I have, it shows DL2 bowls, but no DL4, however from the dimensions given in the posts, and the fact that there are not a lot of threads left for the hot air tube, I'm satisfied my bowl is usable.

I used some modeling clay to see what size o-ring I might need and it is about 3/16" from the lip in the stem to the bottom of the counterbore in the bowl.

For now, I won't worry about fitting a hot air tube.

Now, If only I can get the electroless nickel to activate on the bowl and body!

Dan

[partshunt]

Dan: You could try getting the Viton o ring, its brown in color. Allison Transmissions use them for hi temperatures running transmissions with ATF and they last. I have soaked them in gasoline to test them and they dont change at all. The black o rings beside the brown rings doubled in size, not the Viton. My test was only for a coupla days in fuel and they are doing good so far installed in the bike so far.......Joe

[Duda]

Hx 160

I have a 1917 twin with an HX160. It has a black O ring inside and it seals well and has not swollen. I am looking for the new style cam if anyone has an extra they care to part with. The new style does not have the lever with the 1-2-3 high speed adjustment on it.