Schebler HX181

[indianut]

Good call on the Indian Mag gear. I pulled out a half dozen Indian gears and even though i see several different hubs, the gears are the same. I guess no we know that the J and Indian gears are interchangeable, with a relocated mark! Now for the Carb. i hope Mr.'s Cotten and Tommo do not CRINGE when you hear what I have done. I decided to hone the groove from the bore and it cleaned up at about .020 OS. As you both know the throttle shaft has a Removeable Bushing at the top, but NONE on the bottom. The shaft was in fair shape. All I did was turn the bottom, below the bore, down about .015. I made a new bushing for the top. The BLIND Hole for the bottom of the shaft was worn a LOT! I set the carb up in the Mill and went through the top and bored the lower Blind Hole through to the bowl area. Then I fitted a bushing in from the bottom, honed for the PERFECT shaft fit and soldered a cap over the hole where i went through. I think it came out fine. After I run the whole mess through the Ultrasonic for a couple hours I will put up a couple more pics if anyone wants to see. My NEW question is regarding the throttle disc. I have made a new disc and i have a question about the Notch where the Idle Speed Adjustment Screw comes in. Does the disc close all the way (to the angle) and then the Screw push it open, or does the Idle Speed Screw just make the hole in the notch larger or smaller. I would Guess that is what it does, but have never seen a carb work like that. Thank You for all the excellent advice so fat. I am almost a confident Scheb Model H Hack!!

[Tommo]

The screw does not touch or push open the butterfly but must be a very close fit with just the slightest bit of clearance. The butterfly must shut totally around the carb venturi wall leaving the screw to control the idle speed.
Schebler put a slight knife edge on their butterfly notch but we have never bothered to do that and our butterflys seem to work perfectly.
We bush the bottom hole using the same bush that is in the top, your solution is probably not the way I'd have done it.

[T. Cotten]

... your solution is probably not the way I'd have done it.

Tommo and Indianut!

I do not think that I have ever done any two the same.
But I do try to use Monel for the bushings when I can.
(Unfortunately, my modern allow seems to like to gall upon the original bushings pressed upon the shaft!)

And trying to reproduce the angles to the notch by hand turned out to be the only way I could get the notch accurate at all, as the peculiar angle within the disc, determined by the disc's angled edge, proved far beyond my machinist skills.

...Cotten

[indianut]

OK after putting about 20 hours into this carb, new airhorn shaft, disc (leather now PEEK) and carrier. Machined air valve seat, Honed bore oversized with new disc fitted, made new Float, made new Strap (from a set of Ford Mustang Points,and I know it is not the right color material, but it seems to work well!) and Peek tit to ride the needle lift(?) on the strap, new O/S pin to hold the needle lifter without slop, it actually fired up and sounds pretty good. It is CERTAINLY NOT Dialed in yet, I had to take a break from the 95 Degree temp with 80% Humidity. I see now how important the air valve spring pressure is. I do not understand how you are to dial the knurled knob to change the pressure due to the little stick(?) that locates the knob to the 3 levels for starting(?) because the stick prevents it from turning. The only way I can see to adjust the spring tension is to take the air horn off and use the nut on the inside. What am I missing? Thanks

[Tommo]

The fitting that what you call the stick locates into is in fact a threaded adjuster and you should be able to turn that by twisting the knob while it is fully pressed in.
Only the pre 1916 air horns didn't have this facility and they had three holes of varying depths that the stick/pin locked into.
The giveaway for the adjustable centre nut style of air horn is the 3/16 ball that retains the friction spring and rubbing block that stops the adjuster turning on its own.
If you look around the outer surface about halfway between the hex and the mouth of the air horn you should find this ball blocking a hole there.

[Tommo]

Re mag gears,
I've always been under the impression that the give-away for Harley gears was the 3 holes that the puller goes into to get them off.
I've attached a picture of a genuine factory HD puller and a mag gear and beg the question, Am I wrong in assuming that all genuine HD mag gears had three holes in them?

[indianut]

Thanks Tommo, I thought that may be the way, but due to the freshly honed hole and the precise fit of the shaft if the part is not turned all the way tight the valve does not sit perfect on the seat. Regarding the prior info I read from you the valve must seat perfectly and the shaft should not flop in the bore! What should I do, make some slop in the hole so the valve seats fully when I turn the piece or just use the inner nut by removing the air horn to adjust? Is this an adjustment that should remain fixed once I get it perfect? Sorry for so many questions.

[Tommo]

We use a jig to hold the adjusting nut square in the lathe if we ream/hone that bore and as a result everything stays in alignment.
To try and solve your problem from halfway around the world is very difficult as I'm the sort of person that likes to actually hold things in my hand.
A Model H is like any piece of precision mechanical machinery and to work properly it needs to be repaired so that it works to the specs it was designed to work to.
That said and to answer your question re adjustments once set.
I'd say generally once set the air valve will need little or no adjustment but to do this without the ability to turn the adjusting knob will be a right pain in the butt.
The main things that would require you to adjust it would be differring fuel quality and altitude variations.
Does this help?

[indianut]

OK here's where I am at with my HX181. I have Carefully been through this carb. The Air Valve seats perfectly, regardless of where the knob is. The Bore is Perfectly smooth and the Disc is a Perfect fit. The Idle Speed Screw is fitted to a notch in the disc as perfectly as can be done. The Intake Manifold and Nipples pass the Bubble Test with the new Peek Seals and perfected manifold Spigots. The Bike starts easily. It runs pretty well. The problem is with the idle. The Mix Needle is Hyper-Sensitive! 2 clicks either way make a big change. The further in I turn it (leaner) the RPM continues to rise. The Idle Speed screw is not so Responsive. If it is Idling, the air valve can be adjusted so that if you SLIGHTLY open it with your finger it will either try and die, or if adjusted the other way it will increase in RPM slightly and then try and die. Any Pointers as to where to go now with my adjusting? Also, the tip of the Mix Needle is not perfect, but I have adjusted many carbs with worse needles. Thanks, Indianut

[MMasa]

Back to an earlier post, the HX181 is a carb for a 74" motor and your motor is a 61", right? Maybe you need to be using an HX160 or a DLX20?