Doing some work on my FXR, I had to remove the exhaust, the stud on the rear intake side of the head came out, the nut stayed on the stud. Threads inside the head are OK. No big deal, I go to the Harley dealer get a new stud. Threads that go into the head are not 5/16-18, like the one that came out. The nut side on the new stud is 5/16-24, but the coarse side must be a proprietary thread. A 5/16-18 nut won't go on it, and it's not a metric thread that I know of. Anyone know what that thread size might be.
Sounds like they gave you the wrong stud. Double nut the old stud to remove the stuck nut to ID those threads as well.
Did that, the nut side is 5/16-24 fine thread, on the stud that came out, the coarse thread size id 5/16-18, don't know what the thread pitch on the new HD stud coarse side that goes into the head, but it's not the same (5/16-18 that came out of my head). Aftermarket studs don't have the thread sizes listed.
16715-83 - 5/16" x 18 x 24 x 1-11/16"
Check what part number they sold you if it is not 16715-83 then it is the wrong stud.
i would have taken the old stud with me when buying a new one
Quote from: Scotty on May 20, 2019, 02:43:48 PM
16715-83 - 5/16" x 18 x 24 x 1-11/16"
Check what part number they sold you if it is not 16715-83 then it is the wrong stud.
Thanks for the part # Scotty.
Who knew a simple stud would be difficult to get, didn't think I was going to need a part number LOL. The dealer parts guy must be new.
why not use the M8 Exhaust Stud?
Exhaust stud HD 10900015A ($0.51 ea.) on left,
[attach=0,msg1280321]
Quote from: FSG on May 20, 2019, 04:40:15 PM
why not use the M8 Exhaust Stud?
Exhaust stud HD 10900015A ($0.51 ea.)
Now you are just being cheap Gary :hyst:
true but I like the hex on the end,
easy to put it in and hopefully get it out
also lets the nut sit on the end of the stud while you fiddle to get it started :SM:
Quote from: FSG on May 20, 2019, 06:30:26 PM
true but I like the hex on the end,
easy to put it in and hopefully get it out
also lets the nut sit on the end of the stud while you fiddle to get it started :SM:
:up:
Small block Chevy exhaust manifold studs, 1960's to the 1980's were similar, just rounded at the end to let you get the nut going.
Quote from: Ohio HD on May 20, 2019, 06:42:27 PM
Small block Chevy exhaust manifold studs, 1960's to the 1980's were similar, just rounded at the end to let you get the nut going.
Yes the ARP ones have the rounded end as well and easier to get the nuts started.
Quote from: FSG on May 20, 2019, 06:30:26 PM
true but I like the hex on the end,
easy to put it in and hopefully get it out
also lets the nut sit on the end of the stud while you fiddle to get it started :SM:
I did not even realise that the M8 ones were different until you pointed it out.
Shows how much attention I pay :doh:
Quote from: Scotty on May 20, 2019, 07:42:57 PM
Shows how much attention I pay :doh:
:hyst:
I pointed them out as a good move when the M8 came out a few years ago, yeppers missed it, you may have been busy :SM:
I'm loving the hex on the end..!! :up:
Why did it take this long to get that feature on an exhaust stud..??
Deye, I think the exhaust stud is SAE fine (5/16-24) on the outside, but has a SAE coarse 5/16-18 Aluminum interference thread on the inside. Meaning a 5/16-18 nut will not spin onto it. Similar to the thread type on the case end of the cylinder studs.
-JW
Yeah, I lost a rear cyl stud nut on a long trip west one year (riding an EVO)
Stopped at the next dealer and the parts counter guys laughed at me for wanting a nut for an Evo stud, so deep into the TC generation. They said they hadn't stocked them in several years. Then looked it up on their inventory system to be sure......
In the end, one of shop wrenches had one in his personal tool box and gave it to me for free to get me moving again. Funny how something as small as an exhaust stud nut can be so hard to find at an HD location, lol.
Anyway, may you get it right without much drama....
Mark
I might be missing something, but the only thing special about the exhaust nut is the flange on it. Other than that, it's just a 5/16-24 nut. In fact, for some aftermarket exhaust pipes that don't use the floating collar (Cycle Shack, for example), you can't use the stock nuts, and have to use a plain 5/16-24 nut.
Also, I'm pretty sure the exhaust nuts on my TC are exactly the same as the EVO. Why would they be different?
-JW
Quote from: JW113 on May 21, 2019, 02:25:52 PM
I might be missing something, but the only thing special about the exhaust nut is the flange on it. Other than that, it's just a 5/16-24 nut. In fact, for some aftermarket exhaust pipes that don't use the floating collar (Cycle Shack, for example), you can't use the stock nuts, and have to use a plain 5/16-24 nut.
Also, I'm pretty sure the exhaust nuts on my TC are exactly the same as the EVO. Why would they be different?
-JW
Most Evo's from 83 to 96 I think had a nut and washer not the one piece flange nut we have now. They retrofit and that is what they will sell you if you go into the dealer to buy them now. The dealer he went to obviously had a moron working the parts counter :potstir:
I can't speak to '90 and earlier, but my '91 had the flange nuts, same as my 2004 RK, p/n 7593.
-JW
i know shovels had a problem with loosing studs and stripping the head threads
Shovels only have one bolt. The problem comes from folks calling themselves mechanics, expecting one bolt to hold the exhaust on! :potstir:
Quote from: JW113 on May 21, 2019, 03:08:14 PM
I can't speak to '90 and earlier, but my '91 had the flange nuts, same as my 2004 RK, p/n 7593.
-JW
Did you buy it brand new?
If not there is your answer as stock on a 91 model is washer part number 6016 and nut 7577
7593 is the superseded part number that comes up on the parts database if they look for part number 7577
Also if you are looking at part microfiche on Ronnies etc they show the superseded part number :fish:
Nut 5/16"-24 Flange
Reference: HD-7593
Brand: Harley-Davidson®
MPN: 7593
Condition: New product
Availablility: 56 Items
Supercedes: 7577
5/16"-24
Flange nut
Quote from: JW113 on May 21, 2019, 10:56:08 AM
Deye, I think the exhaust stud is SAE fine (5/16-24) on the outside, but has a SAE coarse 5/16-18 Aluminum interference thread on the inside. Meaning a 5/16-18 nut will not spin onto it. Similar to the thread type on the case end of the cylinder studs.
-JW
That's likely what the dealer has. The studs that came out of the head don't have that interference thread, the nut spins on easily. So my question is, will I damage the threads inside the head installing the stud with the interference ?
Quote from: JW113 on May 21, 2019, 10:56:08 AM
Deye, I think the exhaust stud is SAE fine (5/16-24) on the outside, but has a SAE coarse 5/16-18 Aluminum interference thread on the inside. Meaning a 5/16-18 nut will not spin onto it. Similar to the thread type on the case end of the cylinder studs.
-JW
that they do, at some time in the past I've read it here (not on the internet) in the documentation I have
Quote from: Deye76 on May 21, 2019, 04:19:54 PM
That's likely what the dealer has. The studs that came out of the head don't have that interference thread, the nut spins on easily. So my question is, will I damage the threads inside the head installing the stud with the interference ?
NO
What brand of head are they? If they are stock HD then someone may have put different studs in them at one point.
Even with the slight interference fit they don't take much effort to put in.
But you will have to make the decision basd on what you see.
"What brand of head are they?"
Ultima.
Thanks FSG,
Ultima list the OEM part number 16715-83 as being the same as their stud 66-242 so you should not have a problem based on that.
Quote from: Scotty on May 21, 2019, 07:34:57 PM
Ultima list the OEM part number 16715-83 as being the same as their stud 66-242 so you should not have a problem based on that.
:up: :up:
Also thanks JW113
Another question, if chasing threads inside a head where this interference stud is going is a special tap needed, or will a conventional thread chaser be OK?
That's a damn good question, and have no idea. But if you look closely at the threads on the bolt, you can see that they are formed with a "double edge", for lack of better description. So I imagine that threads in the aluminum hole are standard, and the bolt threads jam themselves in.
I've only had to replace an Evo exhaust stud once, and in fact had to fix a stripped hole in the head while still on the bike. Was not a particularly fun experience, as I recall. Used LOTS of red loctite on the stud.
-JW
Quote from: JW113 on May 22, 2019, 11:27:39 AM
That's a damn good question, and have no idea. But if you look closely at the threads on the bolt, you can see that they are formed with a "double edge", for lack of better description. So I imagine that threads in the aluminum hole are standard, and the bolt threads jam themselves in.
I've only had to replace an Evo exhaust stud once, and in fact had to fix a stripped hole in the head while still on the bike. Was not a particularly fun experience, as I recall. Used LOTS of red loctite on the stud.
-JW
thats where helicoils come in handy
Quote from: Deye76 on May 22, 2019, 10:38:16 AM
Another question, if chasing threads inside a head where this interference stud is going is a special tap needed, or will a conventional thread chaser be OK?
Yes, it's what I've used in the past, none have gone on to be a problem
remember to use a ball inflation needle or similar to blow out debris from the back of the hole
Quote from: FSG on May 22, 2019, 03:15:50 PM
Quote from: Deye76 on May 22, 2019, 10:38:16 AM
Another question, if chasing threads inside a head where this interference stud is going is a special tap needed, or will a conventional thread chaser be OK?
Yes, it's what I've used in the past, none have gone on to be a problem
remember to use a ball inflation needle or similar to blow out debris from the back of the hole
:up: OK good because without thinking first I used a conventional chaser. :embarrassed:
If you use BRASS nuts you will never ever have this problem....
I double nut them
You might if your exhaust bracket breaks and the pipe is hanging on by only the studs...
-JW
cant understand why shovels didnt have the 2 stud set up
Quote from: david lee on June 03, 2019, 04:28:29 PM
cant understand why shovels didnt have the 2 stud set up
Because one stud was a step up from a spring to hold it in place....
Quote from: JW113 on June 03, 2019, 03:20:21 PM
You might if your exhaust bracket breaks and the pipe is hanging on by only the studs...
-JW
I do not see how a brass nut would have anything to do with a busted bracket.
If you have a crappy bracket and it brakes then it will be hanging no matter what you use for a nut.
A brass nut will not seize to a stud .
S.S. will .... they will gall (develop seized spots.)
Personally, I have not ever had it happen.
Yeah the key to not breaking studs is a really good mounting bracket(s). I've not ad any problem with the OE flange'd nuts. I use a little copper anti-seize on them, and re-torque after initial installation. Anti-seize doesn't make them come loose, only prevents galling. If the exhaust has not been off the bike for a year or more, I use a little heat, and penetrating fluid on the nuts.
BTW the the interference threaded stud went in like buttah.
Quote from: thumper 823 on June 04, 2019, 03:55:53 AM
I do not see how a brass nut would have anything to do with a busted bracket.
That's because you missed the point. Brass nuts won't prevent stud damage if a bracket breaks. Agree? My softail exhaust bracket cracked, and the rear pipe was hanging from the studs. It caused one of them to pull loose in the head. Nothing to do with the nuts, and in fact I've never used brass nuts on the exhaust studs and never had one seize. I'm sure there is no harm from using them, but I don't see any necessity either. I'm guessing the engineers that designed the things didn't either.
-JW
I am sure you know the difference between
engineering
Freeze
and then the bean counters.
I have saved my arse quite a few times using SS nuts .
Most other places have had to jig up and do the dirty deed of getting a stud out.
The Harley for argument- is a bean counters toy too.
nothing escapes them.
To each their own.
Quote from: Hossamania on June 03, 2019, 06:49:03 PM
Quote from: david lee on June 03, 2019, 04:28:29 PM
cant understand why shovels didnt have the 2 stud set up
Because one stud was a step up from a spring to hold it in place....
wow ive learnt something else a spring ?
Quote from: david lee on June 04, 2019, 05:46:05 PM
Quote from: Hossamania on June 03, 2019, 06:49:03 PM
Quote from: david lee on June 03, 2019, 04:28:29 PM
cant understand why shovels didnt have the 2 stud set up
Because one stud was a step up from a spring to hold it in place....
wow ive learnt something else a spring ?
It was more of a joke, but many exhausts were and still are held on by springs, especially dirt bikes, possibly even some sport bikes, it allows the pipe to be a bit flexible when bouncing around, instead of rigid and prone to breakage. I'm not sure that any of the really old Harleys were held together using springs, but it would not surprise me.
Quote from: Hossamania on June 04, 2019, 07:57:32 PM
Quote from: david lee on June 04, 2019, 05:46:05 PM
Quote from: Hossamania on June 03, 2019, 06:49:03 PM
Quote from: david lee on June 03, 2019, 04:28:29 PM
cant understand why shovels didnt have the 2 stud set up
Because one stud was a step up from a spring to hold it in place....
wow ive learnt something else a spring ?
It was more of a joke, but many exhausts were and still are held on by springs, especially dirt bikes, possibly even some sport bikes, it allows the pipe to be a bit flexible when bouncing around, instead of rigid and prone to breakage. I'm not sure that any of the really old Harleys were held together using springs, but it would not surprise me.
My old Pan Head was held on by luck :hyst:
Quote from: crock on June 05, 2019, 04:46:48 AM
Quote from: Hossamania on June 04, 2019, 07:57:32 PM
Quote from: david lee on June 04, 2019, 05:46:05 PM
Quote from: Hossamania on June 03, 2019, 06:49:03 PM
Quote from: david lee on June 03, 2019, 04:28:29 PM
cant understand why shovels didnt have the 2 stud set up
Because one stud was a step up from a spring to hold it in place....
wow ive learnt something else a spring ?
It was more of a joke, but many exhausts were and still are held on by springs, especially dirt bikes, possibly even some sport bikes, it allows the pipe to be a bit flexible when bouncing around, instead of rigid and prone to breakage. I'm not sure that any of the really old Harleys were held together using springs, but it would not surprise me.
My old Pan Head was held on by luck :hyst:
Now that made me laugh!
Quote from: Hossamania on June 04, 2019, 07:57:32 PM
Quote from: david lee on June 04, 2019, 05:46:05 PM
Quote from: Hossamania on June 03, 2019, 06:49:03 PM
Quote from: david lee on June 03, 2019, 04:28:29 PM
cant understand why shovels didnt have the 2 stud set up
they got me but on a serious note when i got my 80 shovel back in 84 within 2 weeks both pipes fell off and stripped the threads.used helicoils and still there today
Because one stud was a step up from a spring to hold it in place....
wow ive learnt something else a spring ?
It was more of a joke, but many exhausts were and still are held on by springs, especially dirt bikes, possibly even some sport bikes, it allows the pipe to be a bit flexible when bouncing around, instead of rigid and prone to breakage. I'm not sure that any of the really old Harleys were held together using springs, but it would not surprise me.