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intake nipple sealing

Moderators: Curt!, Pa

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mark59

Posts: 56

Joined: Wed Nov 18, 2009 7:40 pm

Post Mon May 06, 2013 4:40 pm

intake nipple sealing

even'n folks, i had some work done on my U, required pulling topend and now i have a leaky intake, bubbles everywhere! one leak is at the nipple to cylinder, so i assume i will have to remove that nipple and replace it too? seeing how the rivet hole will probably not realign? cylinders are new with one season on them, any tips on removing nipple? don't want to mess up the threads in cylinder. just what does the rivet do and what is the technique to reinstall the rivet, special tool? brass or peek seals? fluid weld or the "the right stuff " on the cylinder threads? any help thru this process will be greatly appreciated. what is the rivet made of? does the threaded insert seat squarely to the intake port in other words do you seat the insert til it is tight / seated and then drill a new hole? well you have an idea where i'm at with this and any thing that you know that i am missing please educate me! just want a quality fix that will last a long time.....thanks Mark
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knucklebolt

Posts: 209

Joined: Tue Feb 12, 2013 8:27 pm

Location: Six miles East of Cheney, Wa.

Post Tue May 07, 2013 3:56 pm

Re: intake nipple sealing

The rivet keeps the insert/nipple from turning when you unloosen your manifold nuts...otherwise they would probably come out with the manifold everytime you took it off. Hard to imagine those threads, between the cylinder and the nipple leaking that badly. Are you sure it's leaking there and not the bushings? I guess you would have already determined that.

If you do take the nipples out and replace them, I wonder what would be the best kind of sealant to put on those threads. ??? Can the nipples just be taken out and re-installed with some sealer?

Just brainstorming here.

ken
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mark59

Posts: 56

Joined: Wed Nov 18, 2009 7:40 pm

Post Tue May 07, 2013 6:48 pm

Re: intake nipple sealing

even'n folks, the nipple at the cylinder was leaking for sure, the last thing i wanted to do was take out the nipple. tonite i ground down the rivet and punched it out, then with great care i was able to remove the nipple with no damage to the cylinder threads, nipple was seated but not tight or tight enough to seal. bubble test clearly revealed that leak and far worse leaks at the brass ferrule. am now waiting for new parts and sealer, and found a nicer intake wye in my stash too. still hoping for some sage advice on any ideas for sealing it up proper, at this time i am considering JB weld or fluid seal which i have on order. if i use peek seals how well do they hold up to a strap mounted carb assembly? in other words do peek seals need extra support at carb to stay put and seal? top end removal surely disturbed the nipple seal, found a black compound on the threads, don't know what it was, but it seemed to have broken down in 11k miles. Mark
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don

Posts: 552

Joined: Fri Oct 01, 1999 12:01 am

Location: Spokane WA USA

Post Wed May 08, 2013 4:33 am

Re: intake nipple sealing

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knucklebolt

Posts: 209

Joined: Tue Feb 12, 2013 8:27 pm

Location: Six miles East of Cheney, Wa.

Post Thu May 09, 2013 3:42 pm

Re: intake nipple sealing

I would certainly put a strap or brace on any carb, also, I believe that when you tighten the nuts on your intake manifold, you want to loosen the base nuts on the cylinder just a bit, then tighten after the manifold nuts are tight.
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mark59

Posts: 56

Joined: Wed Nov 18, 2009 7:40 pm

Post Fri May 10, 2013 2:59 pm

Re: intake nipple sealing

well i got her sealed up.....thanks to all who responded......and the wealth of info found on this board and other boards who you gentlemen participate in. i had also spoke to my engine builder, and bruce from enfield racing and a few others to try to come up with a long term repair. i did order bruce's peek seals for future use. i now have new nipples and brasses from colony and chose to set screw my nipples rather than deal with the rivets and their direct hole thru intake. i got some fluid weld, checked out expando ( i work at a steam rr and they use this on the steam throttles, good stuff but duration isn;t the best ) loctite 620 and of course JB weld.....i chose the 620 loctite for it's retaining qualities and heat range, the set screws are 1/4x 20 cause that's how big the holes were, i seated the nipples and indexed the set screw hole and then with a carbide burr created a divot a little ahead of index mark. all parkerizing was removed from nipples. i did use lapping compound to check for a square fit from nipples to cylinders and that turned out to be a very nice interface. i inspected my intake and found a slight deflection or out round spot that i spent quite a bit of time on to coax back within a few thou of round, other wise intake was near perfect, much better than the deeply scored one i removed. trips to the hardware for rubber stoppers, tubing, and a host of plumbing supplies, plus cussing at failed designs that went pop just when you thought you had it licked...LOL...did my bubble test on each nipple first and then the manifold. at a constant 15 psi i had no noticeable leakage at valves or guides which was surprising i thought, then again the ringing in my ears does rob me of an ability to hear a small leak. thanks again to this great board.....someday i hope i can help someone here and return the favor....mark!
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mark59

Posts: 56

Joined: Wed Nov 18, 2009 7:40 pm

Post Fri May 10, 2013 3:04 pm

Re: intake nipple sealing

i tried to change an error on my last post but it keeps coming up unchanged, the loctite product i used was 620 and not 260
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knucklebolt

Posts: 209

Joined: Tue Feb 12, 2013 8:27 pm

Location: Six miles East of Cheney, Wa.

Post Fri May 10, 2013 3:41 pm

Re: intake nipple sealing

Checking the intake ports for out-of-roundness...I wouldn't have thunk of that. As I have not permanently secured my intake yet, I will check that out. Thanks! I'm running a Bendix on mine and had to get a bit creative with the manifold to do that. Are you using a Linkert or something else? The only reason I didn't is due to the prices they go for now. Once apon a time you couldn't give them away...but I've always had good luck with them.

ken.
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mark59

Posts: 56

Joined: Wed Nov 18, 2009 7:40 pm

Post Fri May 10, 2013 4:01 pm

Re: intake nipple sealing

knucklebolt, i'm running a mikuni VM roundslide 38 mm, i tried to adapt several carbs, but kept coming back to the mikuni, i wanted a snug fit without carb hanging out the side too much. mikunis are cheap ( linkerts are just too expensive for a daily rider ) the 38 is easy to tune and parts are plentiful. i can get parts from most jap shops. this bike fires up one kick warm or cold, of course a primer kick when cold and flip the switch and fire in the hole, anytime it requires any more effort usually the gas is off. most accelerator pump carbs need more room or further out from the cylinders to clear pump linkage....good luck with your fab work, i made a steel adapter from the 3 bolt intake to the two bolt mikuni spigot.......now i need to fab up a stout carb bracket.....got some stainless form some commercial kitchen cabinets, so prebends might make it easier..LOL...Mark oh yeah i'm running an S&S air cleaner with another adapter....trips people out when they notice S&S super is upside down which helps clear gas tank as well
Last edited by mark59 on Sat May 11, 2013 11:31 am, edited 1 time in total.
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Pa

Site Admin

Posts: 4695

Joined: Sun Mar 12, 2000 1:01 am

Location: Ohio USA

Post Fri May 10, 2013 7:22 pm

Re: intake nipple sealing

mark59 wrote:i tried to change an error on my last post but it keeps coming up unchanged, the loctite product i used was 620 and not 260


I changed it for you Bro. And...it worked for me. Pa
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Cotten

User avatar

Posts: 2674

Joined: Thu Sep 30, 1999 12:01 am

Location: Central Illinois, USA

Post Sat May 11, 2013 8:51 am

Re: intake nipple sealing

Mark59!

If that particular Loctite tastes sweet like saccharin, you had better keep an eye on it with modern fuels.

Even tried and true JBWeld is digestible until it has at least six week of cure.

Right now, I lean toward S&S's choice of Permatex's "The Right Stuff".
Even though it says right on the can that it is not for use with gasoline, it has survived perfectly in my soak tests on etched glass.

....Cotten
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mark59

Posts: 56

Joined: Wed Nov 18, 2009 7:40 pm

Post Sat May 11, 2013 11:27 am

Re: intake nipple sealing

hey tom thanks for your response, i have read anything i could find that you have posted over the years on this topic, the virtual indian site has a wealth of info, i looked over the right stuff, actually had in my hands at a parts store, but i wanted something that had more ability to retain a snug/tight fit. i will do a taste test soon on the loctite 620, my nipple to cylinder fit is very nice and i think a mechanical steel to cast iron (steel?) mating surface shall be good for the long term providing the nipples can't loosen up. if this repair screws up and i need to revisit this issue i promise i'll post the info so others can save themselves from extra work and frustration, thanks again Tom...Mark
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knucklebolt

Posts: 209

Joined: Tue Feb 12, 2013 8:27 pm

Location: Six miles East of Cheney, Wa.

Post Wed Oct 09, 2013 9:57 am

Re: intake nipple sealing

I hope all is going well with this. I just had a thought...would it be unreasonable to seal it up with soft-solder?

ken.
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Cotten

User avatar

Posts: 2674

Joined: Thu Sep 30, 1999 12:01 am

Location: Central Illinois, USA

Post Thu Oct 10, 2013 5:23 am

Re: intake nipple sealing

Ken!

Perhaps if you made a crushwasher from it.
Punching a ring from thin lead sheet might work as well.

...Cotten

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