Author Topic: Top Case bracket cracked: overloaded, passenger fault or weak design?  (Read 1152 times)

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Offline BB

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I am sure the bracket was NOT cracked when I first installed the top case this winter. I have NOT actually used the bike that much, perhaps 1,500 miles since December. And I don't recall overloading the top case in any shape or form.

I am not sure if this is a common failure point OR whether my girl accidentally rested her back against the top case, creating another point of stress. 






I am more curious to understand what happened.

I also need the correct term so that I can find a replacement part.

Thanks in advance

 :great:
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Offline MAN OF BLUES

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ooops.. didn't look close enough...

had to go check mine, really can't tell why it broke, they are pretty robust, but I never mounted a big trunk on mine.. soo, can't say.

freak of nature and science I suppose... and too heavy a load on it... bouncing up and down. Does look kinda like it wasn't centered, when it was clamped on, by the wear marks seen and the offset of the break. But I'm sure a good welder could fix it, and even beef it up...

I mounted my trunk (Shad 42L, next size down from yours) to a base angle setup I configured out of offset angle "holey" metal, and mounted my bag to the hard point mounts, under the plastic cover back there, where it was firmly attached to the frame, and un leveraged.. no issue with it ever.  Even held up to a full case of Dead Guy Ale,long neck bottles,  and 2 bags of ice, for a 20 mile jaunt.. down an extremely bumpy road..(couldn't close the cover on the trunk, but did throw bungies over it...)

as they say, YMMV....

 :beerchug: :rotflmao:
« Last Edit: May 02, 2019, 10:36:47 pm by MAN OF BLUES »

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Offline BB

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freak of nature and science I suppose... and too heavy a load on it... bouncing up and down. Does look kinda like it wasn't centered, when it was clamped on, by the wear marks seen and the offset of the break. But I'm sure a good welder could fix it, and even beef it up...

Riding around NYC and potholes could also be the culprit... Great idea about the welding... going to check into that!

 >:D
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Offline MAN OF BLUES

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I tried to find the OEM part number, for that accessory rack, no-joy...
they are out there tho, I had 3 at one time, sold one, then a second one with a back rest and no rack, the last one Rack only is on my COGZilla bike.

sorry about no p/n, I'll check around more...

I'll also dig up the pics of the mount I fabbed up, to mount to the area I mentioned. It will be far better than mounting trunk to the one you have, and only cost $10 in material from Home Depot.

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Offline Greenie

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It's cast aluminum - I broke one one just by over-tightening the cap screws. The maximum weight for the back rack is ridiculously low and I have exceeded that weight by mounting a very large Givi top case with a rack on the top of the Givi with a small Chase Harper also - probably 30 pounds combined. I'm not sure what could have caused your break. Those parts are available - although a quick check on Ebay didn't turn any up.

Offline RenMannV

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I had a different mount on my 02 (been so long I can't recall the brand or whatever) that sheared through the metal.  Never really overloaded the trunk and never had a passenger to lean back on it.  I think it is just weight mounted in a way that it hangs back and off of the mounting points, creating a torsional effect when hitting bumps and such.
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Offline kkja13

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I mounted my top case in the same location as MOB, under the plastic tail cap behind the back seat.
As MOB mentioned this ties it directly to the frame and there is no cantilevering at all. 

Using the 4 locations shown below.
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Offline BB

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I mounted my trunk (Shad 42L, next size down from yours) to a base angle setup I configured out of offset angle "holey" metal, and mounted my bag to the hard point mounts, under the plastic cover back there, where it was firmly attached to the frame, and un leveraged.. no issue with it ever. 

What is required from Home Depot to do the same installation?


I mounted my top case in the same location as MOB, under the plastic tail cap behind the back seat.
As MOB mentioned this ties it directly to the frame and there is no cantilevering at all. 

Using the 4 locations shown below.

I like the solution but I can't fully visualize how this works: could one of you post a photo of the top case mounting hardware and how it goes on the plastic tail?

Thanks in advance!
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Offline MAN OF BLUES

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I mounted my trunk (Shad 42L, next size down from yours) to a base angle setup I configured out of offset angle "holey" metal, and mounted my bag to the hard point mounts, under the plastic cover back there, where it was firmly attached to the frame, and un leveraged.. no issue with it ever. 

What is required from Home Depot to do the same installation?


I mounted my top case in the same location as MOB, under the plastic tail cap behind the back seat.
As MOB mentioned this ties it directly to the frame and there is no cantilevering at all. 

Using the 4 locations shown below.

I like the solution but I can't fully visualize how this works: could one of you post a photo of the top case mounting hardware and how it goes on the plastic tail?

Thanks in advance!

hang tight, I have to drag my other laptop out, and access those.... to post. be back shortly....

It kills me when I can't find pics of stuff I made, searched 2 machines... It's on the oldest machine I have, I'll try to get it found...

but its just a couple of pieces of "holey metal angle" , "L" shaped angle,(like in the photo below) bolted together to make a "U" shape, and laid on it's "side", one for each side mount... to bolt to the holes noted, and also to the metal mounting plate for the Shad... I'll make a quick CAD sketch, as I'm on my machine that has my software... gimme 20 minutes, it's kinda running slow (maxing out my memory)...

I had some scrap, and just made it out of that, but mine was really overkill strengthwise. If you run the rails front to back, like I did, you can get by with very little....I bolted the "L's" together with 3 bolts on each side, (1/4 bolts/lock washer/washer/nuts)... but you may need to pick up slightly longer metric bolts, to use to mount to the 4 holes on the bike.. I added washers below the bottom brackets, to "stand" them off above the plastic...
Easily made, minimal tools, just a hack saw and some black spray paint, and they are robust, and hidden below the trunk.

this stuff ought to work fine

https://www.lowes.com/pd/Hillman-1-ft-x-1-5-in-Plated-Steel-Slotted-Angle/3053613

« Last Edit: May 03, 2019, 09:52:21 pm by MAN OF BLUES »

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Offline MAN OF BLUES

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don't be afraid to flip stuff around, and get creative, I'm not remembering if I had the wings flipped in or out, but I do remember trimming sharp corners off to make it injury preventive...
« Last Edit: May 03, 2019, 10:51:15 pm by MAN OF BLUES »

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline BB

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I'll make a quick CAD sketch, as I'm on my machine that has my software... gimme 20 minutes, it's kinda running slow (maxing out my memory)...

So you created this model in 20 minutes on a machine out of memory?! Not bad my friend... Your CAD skillz are pretty sharp!

I think I got the bottom part and how it attaches to the bike frame: apparently to 4 holes on it - my bike is in CT, can't check it for now.

but you may need to pick up slightly longer metric bolts, to use to mount to the 4 holes on the bike.. I added washers below the bottom brackets, to "stand" them off above the plastic...

But how about the actual fairing and the top case bracket: how do you attach the bracket when the bolted U-shape channels are inside the fairing? That's the part I am not fully understanding the engineering solution... I am sure it is simple and genius.... but I can't visualize how this works...
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Offline MAN OF BLUES

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I'll make a quick CAD sketch, as I'm on my machine that has my software... gimme 20 minutes, it's kinda running slow (maxing out my memory)...

So you created this model in 20 minutes on a machine out of memory?! Not bad my friend... Your CAD skillz are pretty sharp!

I think I got the bottom part and how it attaches to the bike frame: apparently to 4 holes on it - my bike is in CT, can't check it for now.

but you may need to pick up slightly longer metric bolts, to use to mount to the 4 holes on the bike.. I added washers below the bottom brackets, to "stand" them off above the plastic...

But how about the actual fairing and the top case bracket: how do you attach the bracket when the bolted U-shape channels are inside the fairing? That's the part I am not fully understanding the engineering solution... I am sure it is simple and genius.... but I can't visualize how this works...

Thanks, I've been an AutoCad 3D modeler, for well over 20 years...It was my "professional job",  it really only took me about 10 minutes, and most of that was trying to create the "print" to a postable format...

as for the mounting, you have to pull off your old broken "shelf" bracket, remove the rear plastic cover (only held on by a thumb screw, when you look under the seat), then remove the 4 bolts that hold on that black plastic "grid" under there... that frees up the 4 mounting bolt holes shown in KKJA's picture (above where you were first getting confused about the mount) The pieces of my assembly bolt onto the bike, using those 4 bolts... very strong mounting point..

does that clarify more?
you may never have removed the tail cover before, which reveals the factory designed mounting area... which when you see it, it will be crystal clear..  :great: :great: :great:

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Offline JPD

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You leave the fairing off. It attaches with a screw under the seat. When you take the fairing off you will find the stock plastic rack that the bike comes with. You take that off also and then just use the mount locations to put on the angles. My Givi uses spacers at the mount holes then an adapter plate and the Mono-case mount plate. Not sure but I bet you could skip the adapter plate with MOB's angles.

The factory backrest and rack looks good but it is not rated for very much weight. I think someone mentioned that just the case and mount will over load the rear rack. Then if your partner gets slid back into the back rest due to aggressive acceleration that just adds to the load on the aluminum mount brackets.(the ones that broke on you)

Same as MOB said we were typing at the same time

Offline MAN OF BLUES

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the bolts are gonna be about the only need, generic ones when you remove the black rack, the bolts there are shoulder bolts.. they won't work... but save them, and the black plastic part... and the cover and thumb screw... save them all... they become "requested items" later... trust me.

BOLT,SOCKET or hex head work...,M8X23.5 lg.
place 2 washers below the new metal angles you install, at each bolt... 5/16" washers each bolt, work fine.

the washers act as spacers, and make it all level...
his Shad trunk has a metal base plate, with multiple hole patterns, there is a pattern on that plate that will fit the new fabricated bracketry, I was surprised at how many holes the plate actually had... when that's mounted, the plastic cover plate that comes with the shad mount, mounts to the Shad baseplate, to cover everythin. :great:
« Last Edit: May 04, 2019, 01:08:36 am by MAN OF BLUES »

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Offline Kelly E

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The weight rating for the tail rack under the cover is only 11lbs. Up high and behind the rear axle centerline is not the best place to add a bunch of weight to a motorcycle.
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Offline MAN OF BLUES

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 :rotflmao: :rotflmao: :rotflmao:

If you peel of the load rating sticker, you can easily double that rating allowance....maybe triple it if so desired...
 >:D >:D >:D ;)


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Offline Mcfly

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I got a set of brackets from the emporium that are very similar to MOB's last auto cad design. just thicker steel.
That top case is usually mostly empty, except on trips, where it gets loaded with clothes in a vacuum
bag...  That bracket does the job well, and I've never had an issue.  On those trips I do lock my chair
in between the case and a dry bag, even then, works great. 

Not quite sure how much actual weight I've had in that 55L top case, but I'd be just short of jumpin' up n' down
on it to get it shut sometimes.  I worry more about the panniers, that get all the heavy camp gear shoved in them.
Ma Kaw did a wee bit of over engineering (thank goodness!).
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Offline BB

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Ok, back working on the bikes. Removed the broken bracket and the trunk cover. I was surprised to see another trunk plate inside the trunk:





I went to a local home depot and confirmed the availability of L Angles:




But these are steel and I will need to have someone cut them for me. Could someone with this setup please post (or send me) a photo of the final product, without the top box, so I can see how the "room ties together" and also have them cut approximately to the right dimensions?

Thank you in advance!

BB
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Offline JPD

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You should be able to cut it with a hack saw, saws all, jig saw, or an inexpensive angle grinder. MOB cad drawing should give you a good idea then just ues the OEM RACK for your hole spacing.

Offline Jim

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Or you can forego all the trips to the store and cutting, and do what I did. 40 bucks tyd and bolt it on.

https://www.murphskits.com/product_info.php?products_id=279&osCsid=956403b5a7dbcb1deff47fa7853f313b

Offline BB

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You should be able to cut it with a hack saw, saws all, jig saw, or an inexpensive angle grinder. MOB cad drawing should give you a good idea then just ues the OEM RACK for your hole spacing.

I agree, with the access to the right tools it should be a fairly easy job.  I don't have that luxury, so I am trying to work with what I have.

And a photo should also help a lot. I suspect, after seeing that not even Murphy's website has a photo of their rails, that this is a mystery project.
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Offline BB

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Or you can forego all the trips to the store and cutting, and do what I did. 40 bucks tyd and bolt it on.

https://www.murphskits.com/product_info.php?products_id=279&osCsid=956403b5a7dbcb1deff47fa7853f313b

I like that route. I don't like that I don't see the product, so I emailed them asking for photos.

Thanks for the tip.
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Offline GerryG

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I just installed the ones from Murphskits. Very easy install. Z shaped pointing out.

Added this trunk from eBay - https://www.ebay.com/itm/NEW-Large-Detachable-Motorcycle-Top-Case-Travel-Trunk-Vivid-Black/362622211415?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D16ed6a02804c45c6b04edc4e3fba200a%26pid%3D100675%26rk%3D4%26rkt%3D15%26sd%3D362618748478%26itm%3D362622211415&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3A20d14918-77ea-11e9-a34e-74dbd180e7b0%7Cparentrq%3Ac120b2bd16a0a9e3ae8b30c3ffc85066%7Ciid%3A1

Will try to post pictures when I get a chance. I recommend the brackets from Murph. Not so much the trunk. The trunk is ok but it's "universal" mount wouldn't mount without me fabricating a piece between Murph's brackets and it's mount. Also they aren't lights on the back of the trunk, though there is room to install some.

Anyway, point being, the brackets from Murphs seem great.

Offline BB

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I just installed the ones from Murphskits. Very easy install. Z shaped pointing out.
 I recommend the brackets from Murph.
Anyway, point being, the brackets from Murphs seem great.

Thanks for the recommendation. I also need replacement grips from Murphys so I just ordered the grips + mounting brackets.

Cheers! :great: :great: :great:
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Offline connie_rider

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I think you made the best choice as you don't have EZ access to the right tools etc.
The grips you ordered from Murph work great on a Connie.

The "holey" metal that MOB referred to, was called "Tinker Toy" Metal when I was in the Navy..

On mine, I used a piece of aluminum plate as an adapter plate. {Some use a plastic cutting board}
That adapter plate has to be shaped to be approx. 3/4 the size of your trunk mount.
In the adapter plate;
 1) Drill 4 holes that match holes in your trunk mount.
 2a) Drill 4 more holes that match the holes in your bike frame. (where the stock trunk plate was attached)
 2b) At the last 4 holes, stack fender washers to raise and level the adapter plate .
 3) Measure washer stacks {approx. 1/2" for the front stack's  /  3/4" for the rear stack's}, buy correct length bolts, and bolt it all together.
 4) Go ride..

Ride safe, Ted

PS: Here is a discussion where they used a "Store bought version" of my homemade adapter plate;
http://forum.cog-online.org/accessories-c10/mounting-hardware-for-givi-bag/msg666237/#msg666237
« Last Edit: May 16, 2019, 10:27:47 pm by connie_rider »
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