Cobra True Duals Install - Loosen and Re-Wrench?

[dabull]

Hi everyone,

Installed the new exhaust, sounds like i have a leak (lit a borrowed cigarette and tried using it to determine leak(s), best guess looking is yes, best guess listening is yes....

Question is: should I re-loosen all fitting and re-wrench?

Question is: Do i need new exhaust gaskets? Ones on bike now are new....

Thanks fellas

[AlabamaNomadRider]

You shouldn't need new gaskets Derry. I would just try to tighten everything and give it a check. Just sounds like something isn't sealed like it should be.

[macmac]

The crush gaskets leak? If so you may well need new ones. This depends on if they are not in the correct location and were pinched, or if they are in the correct location and are not sealing.

If you changed out to say V&H baggers and didn't check to see if you needed a new flat washer so the acorn nut isn't bottoming on the stud excess tightening may shear/ break the studs.

OEM flanges mixed with V&H bagger weled on pipe flanges often require a addition flat washer to get nut to stud clearnace or the nut will indeed bottom on the stud.

I don't know what you did.

[ringadingh]

Mine leaked a bit once and I got away using the same gaskets and its been fine ever since, try it first and then replace them if you have to.

[dabull]

thanks guys...what is proper torque? I remember 14 foot lbs from somewhere, dealer today told me 14-16 foot lbs,,,might just loosen cans and muffler clamp-them torque to 16 foot lbs..2005 Nomad 1600

Cobra True Duals Mac....

[kudzufarmer]

i don't remember torque, but I "just did it by feel"....tight but not overdone.......probably just loosen and retighten......I don't mean to be insulting in asking this question, but when you tightened all the nuts did you snug them all up first and then tighten to final tourque or did you take the nut to full torque on one nut and then move to the next?

[dabull]

Originally Posted by kudzufarmer

i don't remember torque, but I "just did it by feel"....tight but not overdone.......probably just loosen and retighten......I don't mean to be insulting in asking this question, but when you tightened all the nuts did you snug them all up first and then tighten to final tourque or did you take the nut to full torque on one nut and then move to the next?

Logical question.

Snugged them up firt, evenly (this nut-that nut, this-nut, that nut). Am at 14 Ft Lbs now....2 more foot lbs MIGHT do it, but I certainly don't want to snap a stud!!

[kudzufarmer]

Originally Posted by DaBull

Logical question.

Snugged them up firt, evenly (this nut-that nut, this-nut, that nut). Am at 14 Ft Lbs now....2 more foot lbs MIGHT do it, but I certainly don't want to snap a stud!!

then you did it right..hopefully loosening and retightening will do it....dosen't seem to be something that would be that difficult......maybe try the washer like Mac said.....maybe the nuts didn't fully bottom.

[cactusjack]

Originally Posted by DaBull

thanks guys...what is proper torque? I remember 14 foot lbs from somewhere, dealer today told me 14-16 foot lbs,,,might just loosen cans and muffler clamp-them torque to 16 foot lbs..2005 Nomad 1600

Cobra True Duals Mac....

I torque mine to 14 ft lbs at the heads. I have the muffler clamps about as tight as I dare get them and still have a minor leak from one.

[dabull]

Originally Posted by cactusjack

I torque mine to 14 ft lbs at the heads. I have the muffler clamps about as tight as I dare get them and still have a minor leak from one.

disregard PM and email....LOL Thanks bro.

[ringadingh]

Sometimes after the bike heats and cools a few times the gaskets will leak when new, you can check them, and it may just need a little more tightening to seal up.

[macmac]

Terms: To bottom a acorn means you run out of threads inside the nut, and it locks on the stud. To tighten more means either the nuts threads will shear or you break the stud, or both.

You seat acorn nuts and when they are tight they are seated on a washer that holds the exahust flange in this case, and you hope there is 2 to 3 full threads inside the nut not used. A air gap will be there we hope.

That air gap should be full of antiseize, as well as the threads. Threads are not a perfect fit, there is a gap built in, a big gap in fact, and that gap should be filled with anti seize too.

Different threads cuts/pitch varry as to how closely threads fit each other. Fine threads do fit closer, but still have gaps on purpose, and there are reasons this is true.

This is just one reason penatrant oils can even work at all. There is a place that kind of oil can go.

If this were my bike i would loosen everything, hammer on the cans and the pipes and relieve stress. In this case a concern is the gaskets were not set up straight and have become the problem, but they are difficult to see.

So I guess, I would then tighten the cans, and the pipes last. try again and if there is a leak after 16 foot pounds pull the flanges and check the gaskets.

At the same time I would count threads and make sure the nut with nothing else on the stud can still go in more.

[dabull]

Originally Posted by macmac

Terms: To bottom a acorn means you run out of threads inside the nut, and it locks on the stud. To tighten more means either the nuts threads will shear or you break the stud, or both.

You seat acorn nuts and when they are tight they are seated on a washer that holds the exahust flange in this case, and you hope there is 2 to 3 full threads inside the nut not used. A air gap will be there we hope.

That air gap should be full of antiseize, as well as the threads. Threads are not a perfect fit, there is a gap built in, a big gap in fact, and that gap should be filled with anti seize too.

Different threads cuts/pitch varry as to how closely threads fit each other. Fine threads do fit closer, but still have gaps on purpose, and there are reasons this is true.

This is just one reason penatrant oils can even work at all. There is a place that kind of oil can go.

If this were my bike i would loosen everything, hammer on the cans and the pipes and relieve stress. In this case a concern is the gaskets were not set up straight and have become the problem, but they are difficult to see.

So I guess, I would then tighten the cans, and the pipes last. try again and if there is a leak after 16 foot pounds pull the flanges and check the gaskets.

At the same time I would count threads and make sure the nut with nothing else on the stud can still go in more.

Thx Mac...i reckon i'll run down to lowes and get a couple of lock washers and try that as well ::)

[macmac]

Lock washers will be fine, so long as flat washers are under them. Use anti sneeze.

[dabull]

Originally Posted by macmac

Lock washers will be fine, so long as flat washers are under them. Use anti sneeze.

Flat washers better than split?