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K100-forum.com » Technical, repair and troubleshooting » Engine and transmission » Exhaust Headers, should I be concerned

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Myles Awaye

Myles Awaye
Silver member
Silver member
I was reading speedaddictedberk'd post about his RT rebuild and naked bike conversion ( https://www.k100-forum.com/t7689-the-how-not-to-restore-bikes-thread )

In it he writes about the exhaust header mounting bolts basically disintegrating as he tried to remove the headers. I realized that I never looked at mine upon taking ownership of my K. (Oops)

I went and stuck my head under the bike and snapped a few picks. I can't tell if these nuts and bolts are too far gone to try to remove. I'm going to give them a light scrub with a soft copper wire brush and see if if there is any shiny metal under or if it's rusted deep.

Exhaust Headers, should I be concerned Img_0011
Exhaust Headers, should I be concerned Img_0012

Exhaust Headers, should I be concerned Img_0013

Exhaust Headers, should I be concerned Img_0010

Exhaust Headers, should I be concerned Img_0014
Exhaust Headers, should I be concerned Img_0015


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Father, Art Teacher, Veteran, Aspergers Person, Gamer, Gunner, Rider of the K, Lover of the jugs (i.e. R50/5)

Current Ride: The Vitamin K Project, Code Name: K1000W-TF
VIN: WB1051401F0051627
ENG:FBM098745K342840575
_______________________________
Past Rides: 1970 R50/5, 1975 R90S, 1982 R65LS, 1978 KZ1000, 1986 SRX600
    

Born Again Eccentric

Born Again Eccentric
Life time member
Life time member
They look absolutely normal to me - leave them alone unless you need to remove the pipes.

Located in a pretty crappy place with everything the road can throw up at them combined with some significant thermal cycles in normal use, they will corrode to some degree.If you wire brush them up, they'll only develop a new rusty coat in a very short time.

If you do need to remove the pipes, make sure that you've got spare nuts and studs (and gaskets) available - the nuts won't be re-usable, the studs might (with a little dressing up).


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Exhaust Headers, should I be concerned Uk-log10 Exhaust Headers, should I be concerned Sco-lo15Exhaust Headers, should I be concerned Eu-log10
                              Paul  Exhaust Headers, should I be concerned 905546712

"Heidi" K100LT 1991 (Grey) (VIN 0190172 Engine No. 104EB 2590 2213) - 5th owner. January 2014 (34,000 - 61,000 miles and counting....)
"Gretel" K100LT 1989 (Silver Grey) (VIN 0177324 Engine No. 104EA 2789 2211) - 4th+ owner. September 2015 (58,500miles and counting....). Cat C Insurance write-off rebuild Feb 17
"Donor" K100LT 1990 (Red)  (VIN 0178091 Engine No. 4489 2024) - 6th & final owner (crash write-off now donor bike).   June 2012 (73,000 miles) to November 2013 (89,500 miles)
    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
They'll probably unscrew from the head intact if you attempt to remove them, even after a good shot of quality penetrant. They're available from BMW but a length of 8mm x 1.25 pitch threaded stock can be cut into your desired lengths and then a good quality crush nut replaces the OEM copper version.

OEM shouldered Stud x 8 - 07 12 9 903 964 or 07 12 9 908 133

OEM Nut  x 8 - 11 62 1 744 323

Crush gaskets x 4 - 11 62 7 662 083


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100, '87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R, '04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

Myles Awaye

Myles Awaye
Silver member
Silver member
@Born Again Eccentric wrote:They look absolutely normal to me - leave them alone unless you need to remove the pipes.

Located in a pretty crappy place with everything the road can throw up at them combined with some significant thermal cycles in normal use, they will corrode to some degree.If you wire brush them up, they'll only develop a new rusty coat in a very short time.

If you do need to remove the pipes, make sure that you've got spare nuts and studs (and gaskets) available - the nuts won't be re-usable, the studs might (with a little dressing up).


Two Wheels Better
They'll probably unscrew from the head intact if you attempt to remove them, even after a good shot of quality penetrant. They're available from BMW but a length of 8mm x 1.25 pitch threaded stock can be cut into your desired lengths and then a good quality crush nut replaces the OEM copper version.

OEM shouldered Stud x 8 - 07 12 9 903 964 or 07 12 9 908 133

OEM Nut  x 8 - 11 62 1 744 323

Crush gaskets x 4 - 11 62 7 662 083

Do I need to remove them?.. well....sort of. As part of establishing a maintenance foundation and cleaning out the bike (somewhat thoroughly), I am wanting to replace rusty and corroded stuff with new shiny stuff not so much for fashion but for peace of mind (as much as possible). At the beginning of October I am putting the K up on a block and taking stuff off (tank, seat, rims, forks, and electrical) for the deep clean and resemble. (that's the plan at least). So I am assessing and ordering parts as I find things I want/need to switch out.

Thanks for the part numbers. That is super helpful. I was not sure if those bolts were fused with the header or replaceable. I feel better knowing they can be replaced and I don't need to buy a new block (which I am not inclined to do).

I like this bike and the inner workings were well maintained by the previous owner. They never cleaned it though and it shows on certain sections of the bike.


__________________________________________________
Father, Art Teacher, Veteran, Aspergers Person, Gamer, Gunner, Rider of the K, Lover of the jugs (i.e. R50/5)

Current Ride: The Vitamin K Project, Code Name: K1000W-TF
VIN: WB1051401F0051627
ENG:FBM098745K342840575
_______________________________
Past Rides: 1970 R50/5, 1975 R90S, 1982 R65LS, 1978 KZ1000, 1986 SRX600
    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
They're not bolts, they're chrushable nuts spun onto threaded studs, and those nuts tend to make themselves part of the studs due to heat and corrosion. Only remove them if you need to. If there are no leaks, why bother?


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1970 R60/5, OZ '77 R75/7-R100, '85 K100, '87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R, '04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
"Crushable nuts"?!  Cringe...

BTW, what is special about them besides the fact that they are made of a rare magnetic copper that BMW seems to have access to.  I replaced mine with stainless nuts and lots ofg copper anti-seize.



Last edited by Point-Seven-five on Mon Sep 18, 2017 5:36 pm; edited 1 time in total


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

Dai

Dai
Life time member
Life time member
They're 'Phildas' nuts - the recommendation is to use them not more than five times - if they're in good condition and if you can get them off...

http://www.bolts-nuts-washers.com/philidas%20nuts.htm


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1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

MartinW

MartinW
Life time member
Life time member
If and when you do have to remove them spray them with a 50-50 mix of acetone and ATM fluid. let them soak and repeat a few times. It will give you a better chance of actually removing without damage, but not guaranteed.
Regards Martin.

    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
All this talk of studs and nuts and screws and lube and penetrating is gunna get us an X rating.


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1970 R60/5, OZ '77 R75/7-R100, '85 K100, '87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R, '04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

Holister

Holister
Life time member
Life time member
I agree Dazza. All this K talk is getting me hot. Maybe it's a new classification.... K Rating - Warning. This site contains explicit innuedo and funny bits. 😂


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1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808		  Exhaust Headers, should I be concerned Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

Myles Awaye

Myles Awaye
Silver member
Silver member
@Two Wheels Better wrote:They're not bolts, they're chrushable nuts spun onto threaded studs, and those nuts tend to make themselves part of the studs due to heat and corrosion. Only remove them if you need to. If there are no leaks, why bother?

Yes... this is my concern. If I unscrew the nuts, (yes, you may giggle at that phrasing), will it snap a stud off? This is what I am trying to determine.

But it looks as if those studs are replaceable. Am I understanding correctly?

I feel that Ultimately (at some point) this will need attention. Do I take a chance now and replace rusty parts (on the hope that it's not rusted that deep) or wait until it completely rots out and then I have to replace the block (which I simply can't afford to later)?


__________________________________________________
Father, Art Teacher, Veteran, Aspergers Person, Gamer, Gunner, Rider of the K, Lover of the jugs (i.e. R50/5)

Current Ride: The Vitamin K Project, Code Name: K1000W-TF
VIN: WB1051401F0051627
ENG:FBM098745K342840575
_______________________________
Past Rides: 1970 R50/5, 1975 R90S, 1982 R65LS, 1978 KZ1000, 1986 SRX600
    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
Vitamin K wrote:...it looks as if those studs are replaceable. Am I understanding correctly?

I feel that Ultimately (at some point) this will need attention. Do I take a chance now and replace rusty parts (on the hope that it's not rusted that deep) or wait until it completely rots out and then I have to replace the block (which I simply can't afford to later)?
The part number for replacements studs is in my first reply. There's no reason to replace a block if a stud snaps, which it's unlikely to do. In most cases if you have enough bite on the rusty bit - that once resembled a nut - the studs will unscrew with the nut attached. You then either run a tap through the threads to clean them up or simply screw in new studs. Even in the unlikely event of a stud snapping off there's always Ez-Outs and other methods of removing broken remainders from the threaded hole.

Exhaust Headers, should I be concerned Thread10
Threaded rod
Exhaust Headers, should I be concerned Ez-out10
Ez-out


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100, '87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R, '04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

Two Wheels Better

Two Wheels Better
Moderator
Moderator
Here's a timely link to the online website Visordown, and a fairly good article on potentially siezed fasteners... Visordown


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100, '87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R, '04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

    

Garyk100

Garyk100
Platinum member
Platinum member
Exhaust Headers, should I be concerned Img_1113 Over the last 19 years I have removed my exhaust 5 or 6 times to weld the cracks, I am on my third exhaust, not sure if the cracks are just a K problem or my crappy welding, 
The first time I removed the exhaust I purchased new copper looking rings/gasket things, when I removed the exhaust there were no rings in there, but when I put the rings in there was very little thread to put the nuts on, so I put it back together without the rings, never replaced the studs or nuts and all seems fine, 
My original exhaust had a loud rattle inside, so being inquisitive I got the grinder and cut it open, did not help could not find why it rattles, so I had half a muffler a welder and a cheap alibaba muffler and made this, I like the sound not loud at all but you can hear it now


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The early bird catches the worm, but the second mouse gets the cheese

1991 K100rs16v
1993 K1100LT
    

Myles Awaye

Myles Awaye
Silver member
Silver member
@Two Wheels Better wrote:The part number for replacements studs is in my first reply. There's no reason to replace a block if a stud snaps, which it's unlikely to do. In most cases if you have enough bite on the rusty bit - that once resembled a nut - the studs will unscrew with the nut attached. You then either run a tap through the threads to clean them up or simply screw in new studs. Even in the unlikely event f a stud snapping off there's always Ez-Outs and other methods of removing broken remainders from the threaded hole.

Thank you Two Wheels... and thank you everyone who shared their thighs and experience with this. (oops, typo, I meant "thoughts, not "thighs"...need to keep this a family friendly forum).

I now understand how the head is put together down there and I am not going to freak out about those nuts. (er.... um....  that sounds suggestive too... sigh)



(Stay on topic... stay on topic... )


Getting in to this K is a bit unnerving at times as I learn how the machine is constructed and what its design quirks are. 

I am starting to rely heavily on the members of this community to bring me back down to K equilibrium when I start to panic that I'm in over my head.



Last edited by Vitamin K on Mon Sep 18, 2017 8:56 pm; edited 1 time in total (Reason for editing : Typos)


__________________________________________________
Father, Art Teacher, Veteran, Aspergers Person, Gamer, Gunner, Rider of the K, Lover of the jugs (i.e. R50/5)

Current Ride: The Vitamin K Project, Code Name: K1000W-TF
VIN: WB1051401F0051627
ENG:FBM098745K342840575
_______________________________
Past Rides: 1970 R50/5, 1975 R90S, 1982 R65LS, 1978 KZ1000, 1986 SRX600
    

MartinW

MartinW
Life time member
Life time member
Gary apparently the cops in the US had a problem with header cracks and it was solved by changing the resonance in the pipes. What they did was fit a large jubilee clip around the four pipes. The fix is documented somewhere try the Motobrick site.
Regards Martin.

    

MartinW

MartinW
Life time member
Life time member

    

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