K11 Owners Group

getlunch · Posted: Mon Nov 17, 2008 9:54 pm Post subject: Header flange nuts

I'm in the process of doing the cracking header collector to muffler repair and was wondering if the header nuts are reusable. Some lock nuts I've used on other applications are reusable and some are not. And if these are not, does a copper lock washer and nut work as well, perhaps better. I've had other muffler systems where the lock washer/nut combo never budges until heavy application of Liquid Wrench and a breaker bar. Plus the dealer wants five bucks a nut. Ouch!

Thanks
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Rand
'92 K100RS

Scott_Anderson · Posted: Mon Nov 17, 2008 10:04 pm Post subject:

I think that most everyone here has reused the header nuts. Alot of them, myself included, check them with the torque wrench at each oil change just to make sure they stay tight.
Even new nuts can work loose.
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Ride safe.

1995 K1100LT 0302044
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1997 K1100LT 0302488(R.I.P.)
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chopper_harris · Posted: Tue Nov 18, 2008 4:51 am Post subject:

For a couple of $, why not replace them all with stainless.

IIRC, the OEM nuts are m8, with a 12mm socket size. I fitted m8 with the industry standard 13mm socket size.

Apply a dab of threadlock, and all will be well.
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dave n · Posted: Tue Nov 18, 2008 11:23 am Post subject: header flange nuts

I would use anti seize on nuts - not thread lock - you don't want the studs coming out next time.
_________________
Dave Norris KOG 248
1999 Cagiva Gran Canyon
1993 K1100LT w/Hannigan sidecar
2008 Suzuki DR650

Flying Duck · Posted: Tue Nov 18, 2008 2:39 pm Post subject:

I suspect a thread locker would degrade rapidly under the heat anyhow.
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93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
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Saltcreek · Posted: Mon Dec 29, 2008 8:00 pm Post subject:

If I'm calculating right that torque of 21 nM is only 15.5 foot pounds. That doesn't seem like much.
_________________
Jim

1994 K1100LT Mystic Red, bfd, 37000 miles, sold Sad

2009 Wilderness Systems Zephyr 155 ST
2002 Litespeed titanium

Jim · Posted: Mon Dec 29, 2008 8:17 pm Post subject:

Scott_Anderson · Posted: Mon Dec 29, 2008 10:29 pm Post subject:

Jim · Posted: Tue Dec 30, 2008 12:57 am Post subject:

Oh - is that what I meant? Yeah, that's what I meant...
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Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."

K11Martin · Posted: Tue Dec 30, 2008 5:11 am Post subject:

My header nuts disintegrated while removing them, and on some studs I had to hammer on an 11mm impact socket to get them to move at all.

One of the head studs sheared off in the process, and two more sheared off while trying to extract them for replacement due to corroded threads. This was despite copious amounts of releasing agents, numerous heating/cooling cycles, double locking nuts and the use of some serious stud removers.

DO NOT use thread lock on the studs. It's far better to have them come out inadvertently when attempting to remove a nut, than not have them removable at all.

Brass nuts are used for a reason. Steel ones will promote rust, which you definitely don't want. Brass will cause corrosion due to the proximity of dissimilar metals but in theory only the nuts should suffer. (It must just have been all-year-round use in British weather which had caused mine to deteriorate so much). Far greater a worry is similar corrosion where the steel studs fits into the alloy head. In that situation, a good anti-seize compound should be used.

FYI one of the head studs shown in the picture sheared flush with the head and resisted all attempts at removal.

I ended up drilling and tapping a 6mm thread into what remained of the old stud, then using an M6 bolt cut to length to secure the header flange at that point. I retightened all header nuts (and the new bolt) two or three times after runs, and the bike's now done 4k miles with nothing working loose. Helicoilng would have been (and still is) an option, but so far this has worked, and until such time as I need to remove the exhaust for another reason, it'll stay.
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Daniël V · Posted: Tue Dec 30, 2008 6:11 am Post subject:

For the peace of mind it offers, I get all the nuts and bolts new when I start to replace an exhaust. At the local dealer they are not expensive, something like 8 $ for the lot. (euro pricing, your price point may vary..)

Last time i did it, 4 nuts came off and 4 bolts came out. So i replaced the 4 bolts with new ones, left the old ones in and put fresh nuts on all.

For the minimal money spent this feels like a good way.

HTH, Daniel

AndrewD · Posted: Wed Dec 31, 2008 6:07 am Post subject:

A couple of the nuts on my bike came loose on cobbled roads in Belgium Evil or Very Mad

was a pig to do as you need a deep socket.

The nuts look to be deformed heads to act like a nylock but with the top oval to grip the thread. I did intent to replace them all but I think they will be a P.I.T.A to do, a little rust etc act like thread lock anyway Cool

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AndrewD

1994 K1100RS in Black
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getlunch · Posted: Wed Dec 31, 2008 8:03 pm Post subject:

In my recent repair work I went the all stainless route, nuts, studs, and washers. Partly because it makes sense to me and partly because the dealer was out of stud bolts when I went in for replacements. Mechanic at the dealer seems to think it's a good idea and doesn't see any possible problems. Any metallurgists here with input on reactions, if any between stainless and aluminum?
_________________
Rand
'92 K100RS

Jim · Posted: Wed Dec 31, 2008 11:17 pm Post subject:

not a metallurgist - but I believe aluminum and ss are fairly close on the scale. I believe I posted a link in one of the tech stickies with the info.
_________________
Jim
1997 K1100LTSE 94,000 - still has gremlins!
1995 R100RT Classic 16,650 crashed - repaired!
1992 K75RTP 46,000

"We shall not all die, but we shall all be changed."