K11 Owners Group

[Corkboy]

As the subject says, the topbox rack frame has started cracking at one of the leverage points. Probably from carrying too many shoes for my wife on our trips.

Being a tight git (and only second hand ones are available of unknown origin), I was going to take it off and epoxy in two metal strips, one each side. It looks like, from the parts diagram, that there's a lattice of plastic on the backside of the frame. I was going to cut a groove where necessary to seat the metal, and epoxy it in.

Any thoughts? Has anyone had this problem and how did they resolve it?

As always, thanks for the thoughts
Corkboy.
_________________
'08 K1200GT
'87 K100RS 0140995 (Gone)
'97 K1100LT 0188024 (Gone)
'08 Transalp 700 (Gone)

[Scott_Anderson]

Picture of what you are working on?
I'm trying to picture it in my mind but I'm drawing a blank.
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[Corkboy]

Here is a picture of the part. The red bit highlighted is where the frame has started cracking. Obviously through stress due to the leverage on from the topbox.

As you can see from the opposite frame, where you can see the back of the frame, it has a lot of cross bracing (but not enough)

Hope this clarifies



https://picasaweb.google.com/117199063345477057115/K1100LT?authkey=Gv1sRgCPCHsenjq7yaUw
_________________
'08 K1200GT
'87 K100RS 0140995 (Gone)
'97 K1100LT 0188024 (Gone)
'08 Transalp 700 (Gone)

[Scott_Anderson]

That looks similarly close to the part that Dr. Gui repaired on his LT a few years ago.

I'll see if I can find his post about it.
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[Scott_Anderson]

Here's a pic of the bracket he made. I haven't found the thread where he makes it.....

Well, he made it a kit for Jim here. Here's some pics of what he made.




Here was his final result.

Final result of the Top Case mounting reiforcement.
Two steel vertical braces each side, going from rear lateral case support mounting stud to lower top case frame stud.
With an cross-link screwed.




Now, the whole package (top case and support), flexes a lot less, and provides more support to the passenger.
Next step: put some LED lateral Brake Lights in the vertical braces.
Gui
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[Corkboy]

Wow, that's certainly the way to solve it for good!

Yes, the crack in picture 1 is exactly where mine developed. I must see if Dr. Gui is still here and see if he has dimensions. Otherwise I could rough them up myself from the bike.

I'd have to get them made up as I don't have the facilities or raw materials to fashion them myself.

Thanks for that Scott, it's a great help.
_________________
'08 K1200GT
'87 K100RS 0140995 (Gone)
'97 K1100LT 0188024 (Gone)
'08 Transalp 700 (Gone)

[Scott_Anderson]

His username here is "drmalacarne".
They were posted in his "Riding in Brazil" thread in the pictures forum.

You could try and send him a pm/email message and see if you get a response.

You could also contact Jim here and see if he still has the kit, as he's contemplating parting out his LT after some body damage again.
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[N41EF]

http://www.ebay.com/itm/BMW-K1100LT-Left-Saddlebag-Case-Holder-mount-bracket-k75-46542300037-/111348075133?hash=item19ecdcca7d:g:0d8AAOxyi-ZTark6&vxp=mtr

http://www.ebay.com/itm/BMW-K1100LT-RIGHT-Saddlebag-Case-Holder-mount-bracket-k75-465423000378-/111348077019?hash=item19ecdcd1db:g:6B4AAOxyuR5TarpF&vxp=mtr

$30 ish per side
_________________
2014 R1200RT Water Cooled
2001 R1100S Light
1993 K1100LT. Nissan Ice Blue.(Gone)

[N41EF]

If you want to fix yours, you could use fiberglass cloth (Uni-directional) and then glass in an aluminum bar to give it a little more strength. Then a light sanding and flat black spray paint to cover it.

I'd do both of them and fill in the hollow portion on the back side of both of them.

I have the glass on hand, let me know I can mail you enough in an envelope.
_________________
2014 R1200RT Water Cooled
2001 R1100S Light
1993 K1100LT. Nissan Ice Blue.(Gone)

[Jim]

[Scott_Anderson]

Ah, ok. thanks for the clarification there Jim.
I was hoping the K would live on......

See you soon.
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[Jim]

Yep - it lives on. It's got miles to go before I sleep...
_________________
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."

[Corkboy]

[RobBowker]

OK, I looked down on the far part of my bike this morning and spotted a crack in my '98LT. I don't right now have the patience or the means of executing anything as elegant as the preceding ironmongery but I thought I'd have nothing to lose by trying out a process I have used before in other circumstances.

Having lasted 19 years, I think the BMW design using the materials they have isn't really all that bad. The previous owner had a pillion but I don't and the extra leverage as a backrest may have started the failure before my ownership. Who knows the internal stresses of a bit of cheap plastic? Anyway, I was extremely reluctant to cut away the lattice so I could insert a steel member and fix it in place somehow. The lattice hadn't failed, just its junction with the spar - same place as others have experienced.



I used a 2-part epoxy, in this case Araldite Metal - it is what I had. JB Weld is a popular equivalent. So there was something for the epoxy to hang onto, and to reinforce it, I made a small tab of aluminium with curves and chamfers in most of the right places. Not a perfect fit but close enough - epoxy will fill the voids.





To increase the surface area and mechanical strength (such as it is), I drilled the tab before degreasing both metal and roughed-up (emery paper) plastic.





I know, not a pretty sight. At the time of writing, the epoxy still has another few hours to cure completely. I made a jig and used a house brick to apply a small amount of pressure needed to close the fracture completely though it wasn't enough of a gaping crack to get any real amount of epoxy deeply into.

Naturally, I'll be reporting back on the efficacy of this. Total time taken, about 2hrs.

NOTE: As well as the weight of the top box, the load usually comprises 8 bottles of beer and a loaf of bread or, on days of heightened sobriety, a small backpack with waterproofs, camera and binoculars for a day's birdwatching. I have already removed the speakers from the backrest but I think now it may be time to ditch the stupidly heavy backrest itself - and then figure out a way of beautifying it.
_________________
1998 K1100LT SE
1995 Honda NTV 650 P (now sold)
1986 BMW R80RT TIC (the money pit - sold)
1981 CX500B (sold)
1981 Honda C70 (sold)
1981 Honda C90 (written off on a gravelly bend!)
1960s BSA Bantam D7 (never did get it running)

[SugarHillCTD]

As an addition to this thread, I see the weaknesses that Drake warned me about.

I had fabricated a rear mount on my '92 K-RS for an auxiliary fuel tank but it had a metal fatigue failure 1/2 way through a 1500 mile/24 hour ride.

After asking on here about using an LT rack for a new mount, Drake convinced me that it isn't very sturdy- especially for a fuel tank. I guess I now see visual proof.
He did suggest a Reynolds rack (steel, not composite material) and I found a good used one. Very sturdy, but of little use for the odd shape of the bottom of the LT box.

It is very solid and was up to the task last September when I rode east coast to west coast in under 2 days and then back east again. No problems.
_________________
John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

[RobBowker]

I have a feeling my fix is under-engineered both chemically and structurally. I think the plastic may be polythene and not easily bondable. Now considering a backing plate to reinforce the strut at that point, screwed or riveted through the plastic.
_________________
1998 K1100LT SE
1995 Honda NTV 650 P (now sold)
1986 BMW R80RT TIC (the money pit - sold)
1981 CX500B (sold)
1981 Honda C70 (sold)
1981 Honda C90 (written off on a gravelly bend!)
1960s BSA Bantam D7 (never did get it running)

[Corkboy]