Manifold O Ring Install Procedure

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Mickey Yak
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Manifold O Ring Install Procedure

#1

Post by Mickey Yak » Sat Apr 11, 2009 2:28 am

Gents
Having read through the entire board on the subject of manifold O Ring sealing and air pressure testing techniques I have but one question.
Should the O Rings be greased to allow them to slide into place? Perhaps a little WD-40? What are the tricks of the trade?
Thank You
Mickey yak



Cotten
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Re: Manifold O Ring Install Procedure

#2

Post by Cotten » Sat Apr 11, 2009 2:53 pm

Mickey!

Assemble every thing clean and dry, with no lubes, goobers, or tapes, please!

The trick with a Pan is to roll the O-rings up onto the spigots of the manifold so they can be rolled off into their grooves when the manifold is place between the heads. With the clamps opened but perched on the fins of the heads, you can slide the manifold in, flip the o-rings in place, and then have both hands free to close the clamps.

Although this has been thoroughly covered, just some reminders:
Please use only clamps with #10 screws, as exhaust clamps tend to over-tighten.
And please use JAMES' true viton o-rings, as nothing else survives P4gas.
And most important: please pressuretest as per http://virtualindian.org/11techleaktest.html, as not only will the bubbles help you find the sweet spot where the manifold aligns to seal its best, they will prevent you from over-tightening. Then you can tweak your carb support to mate without bind or stress.

And one last reminder: Bubble test the pancover screw over each intake port, as they can be diabolical, and there is no other way to detect it.

....Cotten
PS: Pan manifolds are a lot easier than your sportster! For it, the trick is to use a hammer handle stuck in its mouth to press it squarely up against the heads while you fiddle with the clamps.
(Installed a Jerry Branch manifold on a Chubble last week, and after four failed tries I was reminded once again why Pans were the last great American motorcycle.)

Mickey Yak
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Re: Manifold O Ring Install Procedure

#3

Post by Mickey Yak » Sun Apr 12, 2009 1:43 pm

Gents
I have the Harley O Rings and aircraft clamps. The clamps have a 3/8 hex head nut and a flat bar the goes in-between them when mounted and tightened held in place with acorn nuts. What do you gents think? Wait and get the James or roll with the Harley O Rings?
Thanks Mickey Yak
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Re: Manifold O Ring Install Procedure

#4

Post by john HD » Sun Apr 12, 2009 2:30 pm

mickey

i would go with cotten's reccomendation, i have had a set of james viton orings on for a year now with no signs of trouble.

they make a nice kit with 2 orings and 2 flange gaskets and a new insulator. the flange gaskets are adheasive on one side making installation very easy.

those clamps may work but are a bit of over kill, the stock type with the little screw is all you should need. overtightening will force the orings into the gap between manifold and heads causing leaks.

john

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Re: Manifold O Ring Install Procedure

#5

Post by Cotten » Sun Apr 12, 2009 5:57 pm

Mickey!

Those are fine 'aircraft' exhaust clamps in your photo
(for a personalized machine; I use them.)

However, they are prone to distort rather than to conform like a lighter clamp, as they are made to compress something wide like hose, with great force.
Many of the cases of head spigot damage can be blamed upon over-exuberant tightening of these style of clamps, as the O-ring and spigots cannot occupy the same space at the same time.

Your manifold o-rings need little pressure to squat and seal, and you want it applied as evenly as possible. The assembly is intended to "float" with the expansion and contraction of the cylinders.
The clamps do not hold the carburetor onto the motor.
Or at least they shouldn't.

Beware of some modern stainless clamps (such as Dixie's) with the proper #10 screw but are 20mm instead of the proper .750, and must be ground narrower by at least a 32" of an inch to fall between the shoulders of the head and manifold spigots.

...Cotten

Mickey Yak
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Re: Manifold O Ring Install Procedure

#6

Post by Mickey Yak » Mon Apr 13, 2009 12:52 pm

Gents
Thanks for the light I am now out of the dark! My last O rings lasted 1 year and the aircraft clamps were just slugged not over tightened. The leak might have stopped had I given the screw a turn. Next time I replace those suckers I will use the James Viston O Rings but I think I will keep the Aircraft Clamps and tighten them using the Air Pressure technique. Have any of you had any luck stopping the O Ring leak with a turn of the screw?
Thanks All
Mickey Yak
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