VL Inlet Manifold Nipples

[Peter Cooke]

Am I correct in assuming that this cylinder wouldn't have left the H-D factory with the, I'm guessing, black sealant you can see at the back of the manifold nipple?
Seems unlikely as whatever it is has gone hard and flaky and would have a direct path into the combustion chamber which can't be good.
It doesn't look like the nipples have been replaced but the valve guides have so it could've been applied then.

I think the next step is to remove the black stuff and do a leak test and see where I'm at. Thoughts??

Manifold Nipple.jpg

[Steve Slocombe]

Dear Peter, it doesn't look like the inlet is seated, so may be an earlier replacement with an incorrect part. It has to come out.

[Peter Cooke]

Dear Peter, it doesn't look like the inlet is seated, so may be an earlier replacement with an incorrect part. It has to come out.

Thanks Steve, so you mean it's too short and should seat against the machined surface of the cylinder so there'd be no groove for sealant etc?

I thought they seated where the larger OD meets the cylinder when you screw it in but that was pure guesswork on my behalf, hence the question.

[T. Cotten]

Am I correct in assuming that this cylinder wouldn't have left the H-D factory with the, I'm guessing, black sealant you can see at the back of the manifold nipple?

There was no evidence of any sealers in any of the H-D nipples that crossed my benches, Peter... (Only NOS Chiefs, and it was white.)

...It doesn't look like the nipples have been replaced...

Your photo doesn't show the rivet, which always tells the story.

I think the next step is to remove the black stuff and do a leak test and see where I'm at. Thoughts??

If it does not produce bubbles under a constant 1 atm, and the manifold and nuts were assemble-able, don't fix it.

Good luck!

....Cotten

[otis71]

Often the rivet leaks. Years of wrenching oblongs the rivet hole. Ream it round and make an oversized rivet to fit. Sealing the threads doesn’t work well because they’re not tapered threads. A little JB Weld on the inner surface where the nipple seats helps and handles the heat.

[Peter Cooke]

Thanks for all the tips gents. I've confirmed that the nipple length, ~ 760 thou, is the same length as the repops available from Replicant Metals so I'm assuming the nipples are correct??
Manifold nuts screw on just fine so no issue there. So the next step will be to clean the crud out, run the bubble test, and see what I get.
Pic of rivet attached.

20250915_143908.jpg

[Buster]

I have replaced both sides on my VL. For what it’s worth, I would collapse both nipples and glue/seal new ones in with JB Weld. Don’t redrill the nipple holes in the new nipples, the nipples will not back out. Fill old rivet hole in spigot with JB Weld. I had to remove a JB Welded nipple and had to use large hammer and chisel. I know I will be criticized for this method.

[Peter Cooke]

...I would collapse both nipples and glue/seal new ones in with JB Weld.

Thanks Buster. Should I need to do that, how did you 'collapse' the nipples, other than very carefully!

I've just got all the bits I need to do the pressure test, but am away this week, so will get onto it upon my return. The results of that will determine what happens next.

[Buster]

With the cylinder off motor, I use Dremel with ball or pointed cutting tip tool and cut three separate equally spaced groves into interior of nipple. Don't get into threads of cylinder, take chisel and hammer and knock in one section, then others. The alternative is You can screw out by starting with chisel and large hammer and then finishing with internal pipe wrench. New Nipple can be installed with internal pipe wrench. Take your time. If the present one does not leak and the manifold fits, I would not replace it.

[T. Cotten]

... I know I will be criticized for this method....

Couldn't you have at least goobered a piece o' rivet head in the hole, for looks, Buster?

JBWeld worked great for me! (But it had to cure several weeks to survive my local fuel.)

Your rivet looks pretty unmolested, Peter!

So please don't attack it unless it or the nipple leaks, as nipple replacement can be quite tedious, and often frustrating; Please review http://virtualindian.org/11techleaktest.html for tooling ideas, especially if you wish to re-rivet properly for posterity.

Note that when the assembly displays a leak, the nipples must be tested separately, as the manifold nuts can cover the seam. A large perforated stopper must be applied, which must be held in manually at 15 psi for a least half a minute to be certain any microleaks have a chance to show themselves.

....Cotten