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Topcase causes the subframe to break..!!

Posted: Tue Apr 03, 2012 7:10 pm
by Thodoras
My KTM dealer advised me not to install on my SMT a topcase, because as he explained to me, the topcase puts enormous pressure at the rear part of the subframe of the bike which is rather weak and causes the subframe to break.
He even showed me a broken one, made by that cause!!!
He even told me that it doesn' t even have to be loaded to have this result. And all that refers to any topcase, plastic or aluminium...

Can this be true???
Had anyone similar experience???

Re: Topcase causes the subframe to break..!!

Posted: Tue Apr 03, 2012 7:27 pm
by ogden
Not on an SMT, but my 640 Duke II snapped its subframe three times in six months and that didn't even have a topbox.

The SMT subframe looks rather beefier - they've effectively doubled up the subframe spars and it doesn't seem to have the same structural design flaw as the 640, but it still has the same basic Y-shaped design unlike, say, a Super Tenere which is V-shaped.

So it's possible, but seems to have been mitigated against to a degree.

Re: Topcase causes the subframe to break..!!

Posted: Wed Apr 04, 2012 4:40 pm
by rancidballbag
It breaks! I've had a Givi topbox on my SMT for well over a year now. Last week (end of March) I noticed it was bouncing about a bit more than it should. I thought it was fixings come loose but no. It was a broken subframe. Both welds on the very back part of the frame (hard to describe) had broken. I tend to overload my topbox but I never expected something like this to happen. I used to overload the topbox on the V-Strom but never had any problems at all.
The breaks are at the back end of the subframe so do not compromise safety IMO.
I have a replacement subframe on order and will try to post pics of the damaged one as soon as poss. Found one on ebay for a hell of a lot less than the official KTM one...
From now on I'm opting for a rucksack (backpack) over a topbox. I will fit the topbox again but it will be a lightweight carrier from now.

Re: Topcase causes the subframe to break..!!

Posted: Wed Apr 04, 2012 5:31 pm
by ultrachrome
Uh oh. I'm using a top box to carry about 10lbs back and forth to work. Can you define overloaded?

Could you post a pic of the subframe damage?

Does this thread describe it? http://www.advrider.com/forums/showthread.php?t=434155

Here's another describing a repair. http://www.advrider.com/forums/showpost ... stcount=66

Have you considered having the original subframe repaired and beefed up?

Sorry for all the questions!

Re: Topcase causes the subframe to break..!!

Posted: Wed Apr 04, 2012 7:48 pm
by ogden
Looking at the photos in those links, the SE has the same design flaw as the Duke II - KTM have drilled through the subframe right at the main stress point and left it with a huge weak spot.

Looking at the parts diagram for the SMT, the same problem isn't there. KTM have wisely added separate lugs for the topbox to be mounted so the same flaw doesn't apply.

If the OP doesn't have a photo of the damage, it might be easier just to highlight which bit in this picture was affected:

http://twitpic.com/95ldgf

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 6:46 pm
by rancidballbag
I have spent the best part of this afternoon replacing my subframe. I can assure you it was snapped. It had snapped at the point where holes had been drilled and not on the welds as I had suspected.
I have pictures and will try to post them. If I fail then I will be looking for help, again, like I did when I had issues with my spring...

Whilst replacing the busted subframe, I also noticed my exhaust system is pretty well fcked as well.
There are splits in the exhaust on both fixing points to the subframe and there is also a split in the 'Y' section.
The more I look at this bike the more flaws I notice.
Again, I have photos.

I urge you all, check your subframe and double check your exhaust system for splits!!!

Either I have the reject of the litter or KTM are palming us all off with sub-standard motorcycles......

Will somebody help me post pics of the busted subframe and the split exhaust please.

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 7:37 pm
by ogden
rancidballbag wrote:I have spent the best part of this afternoon replacing my subframe. I can assure you it was snapped. It had snapped at the point where holes had been drilled and not on the welds as I had suspected.

Will somebody help me post pics of the busted subframe and the split exhaust please.
The holes thing sounds about right - KTM seem to like drilling holes in subframes rather than welding on lugs, and they usually drill them in very, very stupid places.

If you need somewhere to upload photos, the easiest way is facebook if you have an account. Upload the photo, right click it, view image, and copy the URL from the address bar. That'll work regardless of privacy settings. Failing that, sign up with Flickr or Twitpic or something like that.

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 7:45 pm
by rottenjonny
2011 model has a modified subframe - different P/No. so they are trying to resolve the problem once they know about it.

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 8:10 pm
by Scutty
Here are the photos:

Image

Image

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 8:15 pm
by Scutty
This is the 2011 frame:

Image

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 8:27 pm
by ogden
rottenjonny wrote:2011 model has a modified subframe - different P/No.
Good point.

2010 - http://twitpic.com/95ldgf
2011 - http://twitpic.com/960j3h

(2002 Duke - http://twitpic.com/5uhsmk & http://twitpic.com/5t4zgg)

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 10:21 pm
by Scutty
And here are his exhaust photos:

Image

Image

Image

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 10:26 pm
by Thodoras
Scutty wrote:Here are the photos:

Image

Image

If your SMT is a 2011 model then why did this happen??
Did KTM really fixed the problem and stop drilling holes at the wrong places or not???

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 10:31 pm
by ultrachrome
delete me

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 10:37 pm
by Scutty
Not my bike - I am posting them for Rancid as he can't

Re: Topcase causes the subframe to break..!!

Posted: Thu Apr 05, 2012 10:55 pm
by Thodoras
Scutty wrote:Not my bike - I am posting them for Rancid as he can't
Oh. ok then...good for you...

Re: Topcase causes the subframe to break..!!

Posted: Tue Apr 10, 2012 11:21 am
by Bug
More stuff that could go wrong ! KTM need to either have a recall or replace these failed parts as its clearly a design or manufactures fault. Hence the redesigned 2011+ subframe.
KTM need to sort their design and development !
I remember Suzuki had a similiar design fault failure on there Hayabusa rear sub frame and if I remember rightly (?) they eventually sorted it but only after a fair bit of publicity.
I am bit surprised at the exhaust cracks.
I wonder if the rear subframe failure is connected to the exhaust cracking ? As movement is transferred through or not ?

Re: Topcase causes the subframe to break..!!

Posted: Tue Apr 10, 2012 3:04 pm
by Marcelo
I am Sr.structural engineer and just in the visual evaluating of the rear subframe design it is obviously that this failure is a basic error of engineering in SMT 2009-2010 subframe. it´s impossible to understand why KTM engineers put a drilled hole in the cantilever bigger moment region and so close a filet welds?. SMT is a travel motorcycle and they realized that no owner would use the top case? Ktm stores around the world sell the stock 37 and 46 liters top cases for SMT, why?

About the exhaust distributor cracks they have no direct relation with the rear subframe failure. These cracks is probably because a wrong welding process without stress heating relief or a wrong choice of silicon the dump cushion pads design and hardness.

Re: Topcase causes the subframe to break..!!

Posted: Tue Apr 10, 2012 3:18 pm
by ogden
Marcelo wrote:I am Sr.structural engineer and just in the visual evaluating of the rear subframe design it is obviously that this failure is a basic error of engineering in SMT 2009-2010 subframe. it´s impossible to understand why KTM engineers put a drilled hole in the cantilever bigger moment region and so close a filet welds?
It's even more difficult to understand why they did something they'd done at least 7 years earlier on the Duke, with the same results. I understand from chatting to my local dealer that failures were addressed with a redesigned subframe under warranty (I just welded some steel rods inside the frame tubes, since KTM weren't interested in a 9 year old bike), so the fact that KTM repeated the same mistake on other models for almost ten years suggests they're not exactly brilliant at learning from their own mistakes.

Still, it looks like they got there in the end. Until the next time.

Re: Topcase causes the subframe to break..!!

Posted: Tue Apr 10, 2012 3:21 pm
by ogden
Bug wrote:I am bit surprised at the exhaust cracks.
I'm not.

http://www.ktmforum.co.uk/supermoto/172 ... -snap.html