Manifold conversion

[berny]

I have a 48 pan that has had a conversion from the plumber nut to a rubber band
and clamp manifold. The last owner, who recently passed way owned it and rode it regularly since 1965 also gave me the M34tp linkert and plumber nut manifold with the bike. I would like to go back to the linkert, but the Keihn has 2 bolts as does the manifold. Do I change the manifold and put in a new one, o ring etc, or is there an adapter to go from 2 bolts back to the linkert. and will the linkert now stick out to far, or does that not matter. What would you do, because I recently started it, on the third kick, and the bike leaks, the carb overflows and it leaks fuel from the pan gaskets. I found silicone on the latter. so I want to change the pan gaskets - and would rather rebuild the linkert rather than clean out the keihn.
need to know which way to go.

[Jack_Hester]

Berny -

Send your heads to Don Sullivan, Head Hog Inc. He will install new 'plumber' inserts for you. And, they will look like they came from the factory. While they are out for the fix, send your plumber manifold and nuts to Tom Cotten, Liberty Motorcycle Specialties, for Peek seal. They are a must, for a proper seal. Plus, they are a one-time fix, as these seal will never need replacing. Tom can explain the reasons.

Jack

[T. Cotten]

Berny!

I'll second the motion to send them to HeadHog, as it is obvious that some welding is in order.
(Nipple replacement is possibly the most difficult operation in all of vintage motor repair.)

Note that your original steel manifold ('48 -'49 only) has some unique peculiarities. In the attachment you can see a dimple within the bore (painted with a sealer). There are three of these stake marks that were part of the assembly procedure before silver-soldering. All too often these leak air.

Another peculiarity is the malleability of the flange. Note the partial grinding shown in the attachment left ink in an area that corresponds to the idle bleed gallery on the carburetor. Fastener stress commonly bends the ears of both carb and manifold flanges, particularly with phenolic blocks between, but the steel manifolds are so soft that they even produce a mirror image of the carb's distortion!

Because of the soft nature of the metal, the spigots distort and wear from brass ferrules of course. Shown is a replacement cut to fit from PEEK that requires only a fraction of the torque upon the nut to seal, yet still provides the tensile strength at high temps to support and secure the assembly.

Many around the world are turning to this material for this and other applications. Although I offer the reconditioning service, I will gladly post photos of my tooling to anyone who wishes to do the same.

...Cotten

[koanes]

The area that is chipped is not part of the nipple sealing surface and won't cause any harm. If the original nipples were removed without damaging any threads the o-ring conversion can work fine. Any 55^ OEM or replacement manifold will work with your linkert. You will certainly want to check for any leaks at the nipple to head surface, manifold to nipple seal, (o-rings) and the carb to manifold surfaces have to be flat. Overtightening over the years will pull the corners in on the manifold and carb. A properly prepared linkert is a very dependable carb. I have not even removed the bowl from the M74B on my 65 Pan for 100,000 miles. Mr. Cotten has made servicing Linkerts a specialty at his shop and has a reputation for high quality work. If you are looking for a trouble free fuel delivery system, you should contact him.

[berny]

Pan restoration

You guys are great, thanks
I was told recently that the plumber nut manifold was not as good as the later o-ring or bands, do you agree.
Also, 48 pans should not have d-rings. this one does and one is cracked.
also, thie pic shows a defect on the head where the pan screw went thru. should I just not worry about it. this is the only pans screw that is broken on the head

I can only place one pic. I will put the bike on the next reply

Joe

[T. Cotten]

Berny!

When brass was all there was for a seal, a compression gland-nut assembly (plumber's style) was the most secure manifold possible. But... brass is un-forgiving in many ways.

When suitable synthetic rubbers were invented, HD realized they could reduce production costs dramatically by eliminating nipples, rivets, ferrules and nuts with just some gummyworms and clamps. This proved a very serviceable design.

But now digestive fuels eat gummyworms in just a season or two, making them another 'lit fuse'. And the PEEK alternative has eliminated the difficulties of the brass, making it now the superior design.

The bottom line is that an o-ring conversion is an un-necessary and expensive way to depreciate a vintage machine.

...Cotten
PS: Reinforcing ring screw holes are easily helicoiled, and I'm certain that HeadHog can achieve any necessary cosmetic repairs as well!

[koanes]

But if the conversion has already been done and you just want to ride your motorcycle...? For those of us that live in the north, spring is no time for a teardown.

[T. Cotten]

I agree, Kyle,
this is a bad time of year to fix something if it isn't broken!

That's why a quick pressuretest makes decisions so much simpler.

Berny!
If you find leakage between the conversion nipples and the head castings,
a tear-down might be imminent anyway: http://virtualindian.org/11techleaktest.html

Good luck!

....Cotten

[berny]

48 pan teardown

Well, Who is going to Oley, Penn rally this weekend
I am trying to get the headds off before then
I needd to know whats next, I thought the mainfold would come out here, but it looks like the heads have to come off together as a unit. I can slide the S & S manifold up and down, but i do not see it comming out.
when i do, then from what you telling me, we should know if the insert nipples are still threaded or what.

Joe

Ps The manifold rubber bands wont nove anymore, do I need to cut them
also, there is aplastice o-ring between the manifold and inlet. and at the inlet of the head, there appears to be an extension sticking out from the head that does not let me just slide it out. not that i have ever done this before.

[T. Cotten]

Berny!

Why won't the clamps come off the manifold? Cutting the o-rings is normal for convenience, but with clamps removed the manifold should fall out. They appear to be silly two-piecers, enough to cause problems all by themselves.

Are those both latemodel bands AND o-rings? Gawd.

You have Colony adapters threaded into your head castings. Pressuretesting those will help you decide if you need/want to replace them.
You certainly would at least want to go back to OEM style clamps and just o-rings, even if the nipples are sound.

Good luck,

...Cotten

[berny]

48 heads and carb

Thanks for the tip. Both Don Sullivan and Tom Cotton have been most helpful with my restoration, or at least rebuild. Not only have they helped me get the parts off the bike by answering my questions. They were always available, despite me calling during their work day. Kudos to good service and reputable machinists, thank you for the advice and looking to getting the job done. Berny