Author Topic: K75 sidecase modifications  (Read 2555 times)

Offline ScooterNSticks

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K75 sidecase modifications
« on: July 28, 2019, 02:26:34 PM »
My 1992 K75 came with two BMW side cases.  All the locks work but I didn't try to mount them until I took possession of the motorcycle.  That's when I discovered they don't fit.

The problem is caused by the rear rack -- it narrows the space at the end where the cases hook to the mounting bracket.  I've posted a photo below. To get them to mount I'll need to grind off two of the plastic hooks on the back of the cases.  Then they'll mount fine.

My question -- will the loss of two mounting hooks on the cases create an unstable or bad situation?  Doesn't seem like it would but before I start grinding I was wondering if anyone has experience or thoughts on this.
  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline mlytle

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Re: K75 sidecase modifications
« Reply #1 on: July 28, 2019, 02:50:52 PM »
what cases?  what plastic hooks?  picture please.

if stock system cases, they fit.  getting them on the mount can be tricky.
  • alexandria, va
  • 92 K75s, 94 K75s, 96 K1100RS SE (custodian), 09 K1300s
Marshall
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #2 on: July 28, 2019, 03:12:16 PM »
what cases?  what plastic hooks?  picture please.

if stock system cases, they fit.  getting them on the mount can be tricky.

The cases are in a friend's garage right now but they are the standard BMW black plastic cases.  The rear rack mounting is the problem though -- they interfere with the mounting because they restrict access to the end of the bracket -- the rear rack metal makes the opening too narrow for the mounting system on the back of the cases.  Take the rear rack off and they mount fine.

I'll take some more pictures later.
  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
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Offline Scott

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Re: K75 sidecase modifications
« Reply #3 on: July 28, 2019, 04:00:06 PM »
As stated, they can be tricky to fit, except that i know mine fit, sometimes they are such a bitch to get back on I would bet they were the wrong bags or mounting system.  Everything needs to be in perfect alignment, then they just slip on easily.  Of course you could have a mismatch too.  Good luck, scott.
  • SoCal
  • bmw R100r, bmw k75, hondapotamus G/W, XT 500 enduro
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Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #4 on: July 28, 2019, 04:32:11 PM »
I'll try them again.  And measure the opening with a ruler this time to be sure before I start grinding anything.
  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline Scott

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Re: K75 sidecase modifications
« Reply #5 on: July 28, 2019, 04:45:18 PM »
Before you grind anything, maybe find another k75 and with the owners permission of course, compare yours and his, bags and mounting system that is.  Good luck again.  scott.
  • SoCal
  • bmw R100r, bmw k75, hondapotamus G/W, XT 500 enduro

Offline Scott

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Re: K75 sidecase modifications
« Reply #6 on: July 28, 2019, 05:20:25 PM »

* k75 Rside mount_001.jpg (51.73 kB . 768x432 - viewed 180 times)
* k75 Rside bag_001.jpg (56.62 kB . 768x432 - viewed 176 times)
Here's a pic of the backside of the bag and its mount, right side, if it helps.  scott
  • SoCal
  • bmw R100r, bmw k75, hondapotamus G/W, XT 500 enduro

Offline Laitch

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Re: K75 sidecase modifications
« Reply #7 on: July 28, 2019, 05:32:27 PM »
The mounting obstruction is probably the metal or plastic support indicated within the arrows in this photo although I can't see it clearly in the latest photo Scooter submitted. Please verify.


The hooks might be one of the sections of the case's hooked mounting rail indicated by the arrows in this photo.


If so, the rear rack mount does not seem to me to be OEM. Grinding of forward sections of the case's mounting rail would place more weight-carrying load on the forward rack latch, destabilize the case when it receives road impact and lower the resale value of the case in general.  If you chose to do that, I'd recommend securing the case to the rack's forward vertical reach with a screw that goes through the case into a fitting embedded in the member. That will stop the case from being ejected by rough road travel and also will take load off the forward attachment hinge.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
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Offline johnny

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Re: K75 sidecase modifications
« Reply #8 on: July 28, 2019, 05:39:12 PM »
greetings...

if thats a k1200gt wheel on there that could be the problem...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Martin

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Re: K75 sidecase modifications
« Reply #9 on: July 28, 2019, 05:44:30 PM »
I'm with Laitch non OEM rack. It would be better to either change the rack or modify it rather than modify the tragkorbs or their mounts. A couple of pictures of the rack would help.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline mlytle

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Re: K75 sidecase modifications
« Reply #10 on: July 28, 2019, 06:41:10 PM »
agree.  looking at the picture of the bike in his other thread.  looks like the non-oem rear rack mount is intruding on the space for the side case hangers.  ditch or hack up the rear rack, don't cut the plastic side cases.
  • alexandria, va
  • 92 K75s, 94 K75s, 96 K1100RS SE (custodian), 09 K1300s
Marshall
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #11 on: July 28, 2019, 06:59:17 PM »
Here is the side rail and a shot showing the narrowing between the rail and the rear rack mount.  I'll have to get shots of the cases later.

  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline Laitch

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Re: K75 sidecase modifications
« Reply #12 on: July 28, 2019, 07:14:40 PM »
I'll have to get shots of the cases later.
Your photos make clear the cause of obstruction. I don't need more photos of the cases. If that were a Reynolds rack designed for the K75, there would be sufficient room for the case mounts to slip onto the top of the z-rack It might be that your case mounting technique needs refinement. Post some photos of the rear rack itself and look for identification words or numbers stamped upon it. The profile shot of your moto in the cornfield isn't quite enough to identify it completely.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #13 on: July 28, 2019, 07:45:46 PM »
I've examined the rear rack and can find no brand, writing or inscriptions on it.  It is definitely the culprit.  It's sturdy but obviously not a BMW product.

If it's not going to work with the side cases, where might I find a rear rack that will?

Here's the images of the rear rack and cases.

Thanks for your help!

  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline johnny

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Re: K75 sidecase modifications
« Reply #14 on: July 28, 2019, 07:55:49 PM »
greetings...

the model is stamped into the steel... 3 numbers... 240... 241...

k75 = 240
k100 2v =240
k100 4v = 241
k1100 = 241

the 4 valve motobricks have a wider rear wheel is why the 241 is too wide on a k75...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Martin

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Re: K75 sidecase modifications
« Reply #15 on: July 28, 2019, 07:59:43 PM »
+1 Jo it is a Reynolds rack made for a 4V brick. I believe that by adding spacers to the z rack and pushing them out you might get the rack to work.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #16 on: July 28, 2019, 08:08:21 PM »
greetings...

the model is stamped into the steel... 3 numbers... 240... 241...

k75 = 240
k100 2v =240
k100 4v = 241
k1100 = 241

the 4 valve motobricks have a wider rear wheel is why the 241 is too wide on a k75...

j o

I look a flashlight and went all over the rack.  Finally found "240" stamped in the metal on an inside surface.  So it's the correct rack for the bike.
  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #17 on: July 28, 2019, 08:10:34 PM »
+1 Jo it is a Reynolds rack made for a 4V brick. I believe that by adding spacers to the z rack and pushing them out you might get the rack to work.
Regards Martin.

The only way I can see the side case mounting is to increase the distance of the Z rack from the Reynolds rack.  Without it the case mounts are stopped from reaching over the Z rack by 1/4 of an inch. 
  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline Laitch

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Re: K75 sidecase modifications
« Reply #18 on: July 28, 2019, 08:13:06 PM »
If it's the incorrect model for your moto—as johnny and Martin have indicated—it might still be modified to work by cutting it and welding in an offset for case clearance. That's an easy task for an experienced welder.

What you can find as a substitute rack depends upon on your intentions. Siebenrock sells a rack for the K75 to accommodate the case it sells, if you want to mount what The Mighty Gryphon calls the dirigible-sized case.

I think you might make your current setup function after alteration by somebody competent. It would help you if somebody posted a video of themselves mounting OEM sidecases on the z-rack so you could see the process.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #19 on: July 28, 2019, 08:20:29 PM »
If it's the incorrect model for your moto—as johnny and Martin have indicated—it might still be modified to work by cutting it and welding in an offset for case clearance. That's an easy task for an experienced welder.

What you can find as a substitute rack depends upon on your intentions. Siebenrock sells a rack for the K75 to accommodate the case it sells, if you want to mount what The Mighty Gryphon calls the dirigible-sized case.

I think you might make your current setup function after alteration by somebody competent. It would help you if somebody posted a video of themselves mounting OEM sidecases on the z-rack so you could see the process.

It appears to be the correct "240" model rack.  If that's the case it seems to point to operator error on my part in mounting the case.  I've fiddled and fiddled and don't see how it's possible to mount due to the lack of clearance between the z rack and Reynolds rack.  Seems physically impossible.  I'll continue to search for instructions on how to mount the cases.  Maybe there's hope for me yet.
  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
https://scooterinthesticks.com

Offline Laitch

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Re: K75 sidecase modifications
« Reply #20 on: July 28, 2019, 08:27:47 PM »
Here's a 240. Note the tabs at the arrows. Does yours have them?
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Laitch

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Re: K75 sidecase modifications
« Reply #21 on: July 28, 2019, 08:32:47 PM »
Maybe there's hope for me yet.
I'm not certain about you, but most steel parts can be altered to improve or adapt their function. I doubt if this one is an exception.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline ScooterNSticks

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Re: K75 sidecase modifications
« Reply #22 on: July 28, 2019, 08:38:59 PM »
Here's a 240. Note the tabs at the arrows. Does yours have them?

Yes, there is a tab on each side where an attachment is made to the Z rack.

Here's the 240 marking.

  • Boalsburg, PA
  • 1992 BMW K75, 2006 Vespa GTS 250ie
My Blog: Scooter in the Sticks
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Offline johnny

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Re: K75 sidecase modifications
« Reply #23 on: July 28, 2019, 08:56:00 PM »
greetings...

oe baggs are hard to slide on for the novice bricker... and the 240 reynolds rack can complicate that...

with z bar lock open you have to hold the bottom of the bagg with both hands... start as far forward as possible... commence to twerking until it slides in there then slide it back and close the z bar lock...

if it wont go you may need to remove the reynolds rack and reinstall it all square and the like... then your baggs oughtta go on as long as you use the 2 hands twerk method...

if it was my moto i would sell that reynolds rack and put the iconic 22 on there...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny
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Offline Martin

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Re: K75 sidecase modifications
« Reply #24 on: July 28, 2019, 09:03:25 PM »
+1 on the 22Lt one of the best things I fitted. However another Bricker had the same problem with fitting the 240 rack to a 75. He added spacers to the mounts to give clearance. It is possible to make it fit by either adding spacers or a bit of cutting, hammering, welding, bending and a bit of paint. Start with a realign and adding spacers.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.
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