What do you think about my nipples?

[Knotthed]

Seriously though, I am very green with the old bikes and I don't want to mess something up to bad. So I'm looking for input.

I'm concerned that the integrity of the threads is not there.

The nuts will go on, but I'm afraid when it comes time to put it together that it might strip?

I want to make sure I do the right thing before I shell out big $$$ for plating.

Let me know what you think.

Obviously one cylinder is worse than the other so I tried to put the majority of the pics from the worst one.


Thanks in advance.

[23JDCA 808]

Welcome to the group. What is the year, make and model we're dealing with here? ...bill in oregon

[Paps]

Have you wired wheeled them up yet ?

[yhprum]

They dont look too bad to me. Maybe clean them up a bit with a thread file and remove the rust.
Steve

[bobdo]

Knotthed,
I know the feeling, its wise to tap into the knowledge base here before jumping in.
There are others more capable than I, but they look good to me. I'd suggest getting a better look or image to share of the worst area after a bead blast or wire brush cleaning. I tend to leave well enough alone. -Bob
( @ )( @ )

[T. Cotten]

Successful nipple replacement is the most difficult operation in all of vintage motorcycle motor repair. To determine if the nipples themselves are sound, please bubble-test them as per http://virtualindian.org/11techleaktest.html.

The need for excessive torque upon the gland nuts is greatly relieved by using a space-age material called "PEEK" for the seal ferrules, such as are available from http://www.enfieldracing.com/8.html. The original design is un-changed.

If you have no leaks between the nipples and the casting or rivet, and you have any reasonable thread-grab with quality gland nuts, and the flat faces can be reasonably dressed smooth,.... Do NOT fix them!


....Cotten

[Knotthed]

They are from 36 chief.

So it looks like I need to glass bead and then retake some pictures. I wish there was a human eye version of pictures. Being that pictures never do justice to what the human eye is capable of.

I wanted to get the pictures up because I was not sure if the bad side was even worth testing.

It also looks like I will have to fashion an apparatus to leak test them.

Cotten, do you think I could use a rubber stopper type of thingy to apply the air as my cylinders are off and the valves are out. It would appear that as long as I have positive pressure in the chamber that it wouldn't matter if I have a leak on the top side just to check the nipple to cylinder interface. Maybe an o-ring and some steel or plexiglass over the valve hole on the head side of things, with a bar clamp to the valve guide?

I also know that I will need new nuts as there are definate chisel marks in the ones that I have.

Thanks for the replys.

[T. Cotten]

Cotten, do you think I could use a rubber stopper type of thingy to apply the air as my cylinders are off and the valves are out. It would appear that as long as I have positive pressure in the chamber that it wouldn't matter if I have a leak on the top side just to check the nipple to cylinder interface.

Exactly.
If putting a valve back in is not practical, then I use stoppers in both the seat and guide, and hold them both in with a vise or C-clamp.

A stopper is the only way to test the nipple itself, of course, as a nut would cover the interface.

Chiefs usually don't leak. It's Sport Scouts and Harleys that had problems surviving generations.

If your nipples have *most* of their threads, they will probably work fine with compliant ferrules. The threads themselves seal nothing.

Good luck!


....Cotten

[moldthread]

Hi Cotten,

Thanks for the plug.

I just want to let everyone know that because of the cost of the molds, I only make seals in the stock sizes, 3 for H-D, and 3 for Indian.

If your manifold is worn, or you need seals for earlier models, Tom Cotten is the only way to go, as he machines them from bar stock after he trues up your manifold.

I have run some tests on the PEEK seals for a Indian Chief, and with 20 psi air, they seal at about 20 ft-lb torque, while the brass are still leaking at 60 ft-lb.

He also custom machines the good "unsinkable" NITROPHYL floats for the schebler carbs.

Bruce
www.enfieldracing.com

[Knotthed]

Here are pictures of blasted threads and pressure testing.

This one does not appear to leak. Will carbon buildup on the back side/inside give a false positive? I set my regulator to 20psi at free flow so it should be slightly over 20psi when sealed up. I did not see any bubbles with the soapy water - like ckecking a flat tire or slow leaky tire, or bead leak.

I hope you can see the threads better now. Are the threads good enough not to have any problems down the road if I go with PEEK seals?

Thanks again

[Paps]

Replace them. Paps

[T. Cotten]

Yep thems ugly.

Good thing hardware ain't self-conscious or vain.

If the thoroughly cleaned nipples pass a sustained bubbletest under constant pressure,
and nuts will even screw on....
(I suggest stiff wire wheel-brushing the nipples before trying some worn nuts, in order to 'roll' the corrosion 'mill profile', and any burrs, as smooth as possible. And lube too, of course.....)

Then I advocate not fixing them.

Even if annealed brass ferrules were all we had.
Nipple replacement has too many risky, tedious, and costly pitfalls to sacrificed nipples that don't leak, and will still accept a nut.

Even if there are micro fissures that must be sealed with a fuel-proof goober, it would still be my choice to leave them be.

....Cotten
Oh yeah:
The faces of the nipples should be dressed with a stone as smooth as possible, even if PEEK ferrules are chosen. They will seal against a rough surface, but it will require dressing away much more of the seal than desireable in order to re-use the seal in the future.
PEEK seals used against an unblemished surface will require very little more than a quick scrub on some 220 grit "wet-or-dry" before a light greasing and re-assembly.

I have yet to hear of anyone wearing any out. But its only been a decade since anyone first tried PEEK. (afaik)

[big jesus 151]

Hello Knotthed

Hey Don, I didn't recieve your pics so came here instead. It seems the fine folks from this forum have got you under control. I would clean & run them. I have actually ran on worse threads, have to be gentle..Have fun Carl Pusherman

[Paps]

Hey Don, I didn't recieve your pics so came here instead. It seems the fine folks from this forum have got you under control. I would clean & run them. I have actually ran on worse threads, have to be gentle..Have fun Carl Pusherman

Not me ..... Those threads are so broken up, there isn't enough material contecting the full lead of the thread. Not only is the lead of a thread the measurement between thread peeks, the lead of a thread is the starting point [ beginning ] flowing continuiosly throughout the thread to the end of the thread. This continuance is the strength of the thread. When material is missing all along the thread, the existing material will break away under load.

[Knotthed]

I appreciate everyones responses and view points, keep them coming.

Paps,

That is my big worry! They are indeed in very bad shape. My gut tells me to replace them, but as I stated in the first post I am very green to the old bike world and have no experience with this at this point in time. I have the desire to do as much of this work as I can or I will not learn much about the old bikes and I don't want to be just someone that owns an old bike. I want to be able to work on them. It gives you a sense of accomplishment that cannot be provided any other way.

If someone can enlighten me with their success and failure stories for nipple replacement, I would really appreciate it. Any step by step instructions would also be great.

Ultimately this is something that I want to weigh the pros and cons and make the best educated decision that I can from drawing on the AMCA communities information.

Thanks again,