2015 KTM 250SX - Snapped linkage arm

K22
Profile picture for user K22
Posts
29
Joined
7/9/2014
Location
AU
K22
Edited Date/Time 9/26/2014 10:34pm
Snapped the linkage arm on my new 250, any thoughts?



|
JBernard_401
Profile picture for user JBernard_401
Posts
1317
Joined
10/29/2013
Location
Boulder, CO, USA
JBernard_401 9/11/2014 8:00am
9/11/2014 8:00am
thats intense! never seen that before.
on a jump?
mx5471
Profile picture for user mx5471
Posts
985
Joined
7/10/2008
Location
USA
mx5471 9/11/2014 11:50am
9/11/2014 11:50am
I'm thinking you landed it there on a rock or something like that. But you would remember that. Or maybe a bad casting that finally gave way.
privateerconnection 9/11/2014 12:13pm
9/11/2014 12:13pm
By looking at the condition of the bolt I am gonna take a guess that you have never greased the linkage bearings before. Possibly had the linkage bearings seize up and the force when you land off a jump has to go somewhere. Just a thought. I have seen this before on a bike that never had the linkage greased. These bikes come from the factory with NO grease in them. The first thing we do with all new bikes is FRAME them and tear them down and build them back up making sure to grease all bearings and lube all bolts and etc.
Paw Paw 271
Profile picture for user Paw Paw 271
Posts
3632
Joined
4/3/2013
Location
Benton, LA, USA
Paw Paw 271 9/11/2014 12:16pm
9/11/2014 12:16pm
I would suggest that the linkage hit something very hard. I see damage to the bearing , seal, bolt and the linkage. I also noticed a lot of sand in the bearings and seals.
These parts don't look like they came from a "new 250".

Paw Paw

The Shop

See All »
mx5471
Profile picture for user mx5471
Posts
985
Joined
7/10/2008
Location
USA
mx5471 9/11/2014 2:21pm
9/11/2014 2:21pm
I noticed that bolt too Paw Paw 271, and the condition of the parts, and thought he might have got the bike used, and the guy he got it from never did anything there. Or maybe the previous owner hit something that damaged it, and it finally let go. I never thought about it being seized, causing that damage. You are right. The energy is going somewhere. But, I guess my idea of hitting it some hard object, doesn't make sense either cause he would have known it right then. I'm just curious. I have never seen that and I would really like to know how it happened.
K22
Profile picture for user K22
Posts
29
Joined
7/9/2014
Location
AU
K22 9/11/2014 4:18pm
9/11/2014 4:18pm Edited Date/Time 9/11/2014 6:29pm
Hey all, bike is a brand new 2015 KTM 250SX with 8 hours on it. Luckily enough it didnt fall on a jump, it must of initially gave way then hit a big bump and it just shattered. from what i can gather one of the arms on the linkage has failed which has then put all of the suspension force onto the 'dogbone' which then blew to bits.

K22
Profile picture for user K22
Posts
29
Joined
7/9/2014
Location
AU
K22 9/11/2014 4:31pm
9/11/2014 4:31pm










Crush
Profile picture for user Crush
Posts
21104
Joined
4/26/2009
Location
Sydney, AU
Crush 9/11/2014 5:57pm
9/11/2014 5:57pm
Wow!
j368
Profile picture for user j368
Posts
575
Joined
7/13/2014
Location
Tulsa, OK, USA
j368 9/11/2014 6:36pm
9/11/2014 6:36pm
That's crazy, never seen anything like that. Reminds me of David Pingree casing the jump and broke the forks off his bike.
rocketsocks26 9/11/2014 6:47pm
9/11/2014 6:47pm
I ll tell ya what, the bolt dust seals look werse than bikes ive had with 100hrs on it lol. What did u land on? It almost looks like the the link is bent, did u over tork it ? And not have the bolt seated?
domoguchi
Profile picture for user domoguchi
Posts
242
Joined
12/24/2012
Location
USA
domoguchi 9/13/2014 3:07am
9/13/2014 3:07am Edited Date/Time 9/13/2014 10:45am
Lack of lubrication. By the looks of the bolt, proper maintenance was never or poorly performed leading to excessive heat build up leading to metal fatigue and eventually failure of the component... Or you smashed the hell out of it on a rock and cracked it ...either iway it was destine to fail...
slipdog
Profile picture for user slipdog
Posts
10054
Joined
7/25/2009
Location
Nor Cal, CA, USA
slipdog 9/13/2014 8:28am
9/13/2014 8:28am Edited Date/Time 9/13/2014 8:31am
Since we're all guessing here, I'll say it has nothing to do with grease or maintenance. KTM's have an obvious issue with the linkage hanging too far below the swingarm, so much so that Fastway makes an adjustable pull rod that has a built in skidplate for the knuckle the shock clevis bolts to.

Maybe you cased that knuckle on something hard enough that it compromised the casting and the stress eventually led to total failure. I couldn't say which cracked first, the pull rod or the knuckle, but either way it would've completely failed pretty quick.

(edit: Actually the pull rod would've had to have failed first, like you said. That's why everything bent the opposite way and the torsion ripped the knuckle apart.)
bd
Profile picture for user bd
Posts
6036
Joined
4/6/2007
Location
Las Vegas, NV, USA
bd 9/13/2014 8:54pm
9/13/2014 8:54pm
Maybe just freak manufacturing issue and fell out of six sigma. I am betting KTM will take care of this.
Brad460
Profile picture for user Brad460
Posts
4475
Joined
5/15/2012
Location
Richfield, WI, USA
Fantasy
263rd
Brad460 9/14/2014 9:56am
9/14/2014 9:56am
No way no how that the linkage froze up and caused that failure after 8 hours...come on guys..

Anyways agree with bd- likely a manufacturing issue, perhaps a small inclusion in the material that caused a stress riser..
Matt Fisher 9/14/2014 4:58pm
9/14/2014 4:58pm
slipdog wrote:
Since we're all guessing here, I'll say it has nothing to do with grease or maintenance. KTM's have an obvious issue with the linkage hanging too...
Since we're all guessing here, I'll say it has nothing to do with grease or maintenance. KTM's have an obvious issue with the linkage hanging too far below the swingarm, so much so that Fastway makes an adjustable pull rod that has a built in skidplate for the knuckle the shock clevis bolts to.

Maybe you cased that knuckle on something hard enough that it compromised the casting and the stress eventually led to total failure. I couldn't say which cracked first, the pull rod or the knuckle, but either way it would've completely failed pretty quick.

(edit: Actually the pull rod would've had to have failed first, like you said. That's why everything bent the opposite way and the torsion ripped the knuckle apart.)
Agreed. Likely at some point in time something smacked the pullrod hard enough to bend it slightly, fatiguing the metal.
harrowguy 9/15/2014 7:23am
9/15/2014 7:23am
Love the guys saying it was because he didnt grease it lol
It had 8 hours on it!!

Pit Row

See All »
Hal_396
Profile picture for user Hal_396
Posts
42
Joined
4/23/2014
Location
Cedar Creek, TX, USA
Hal_396 9/17/2014 6:38am
9/17/2014 6:38am
Brad460 wrote:
No way no how that the linkage froze up and caused that failure after 8 hours...come on guys.. Anyways agree with bd- likely a manufacturing issue...
No way no how that the linkage froze up and caused that failure after 8 hours...come on guys..

Anyways agree with bd- likely a manufacturing issue, perhaps a small inclusion in the material that caused a stress riser..
X2. That stuff looks like it has more than 8 hrs on it but the OP says it has 8 hrs so we have to go with that. I do hope KTM makes good on this. Let us know the outcome please.
NHtoWA421
Profile picture for user NHtoWA421
Posts
576
Joined
8/4/2014
Location
Bremerton, WA, USA
NHtoWA421 9/18/2014 8:16pm
9/18/2014 8:16pm
I wonder if the linkage bolt was loose from assembly. That could cause every bump to essentially smash the bolt againdt the bearing/link. this could quicly cause cracks to develop and once cracked that link could let go rather quick.
NHtoWA421
Profile picture for user NHtoWA421
Posts
576
Joined
8/4/2014
Location
Bremerton, WA, USA
NHtoWA421 9/18/2014 8:18pm
9/18/2014 8:18pm
post up a close up of the fracture surface if you have one. Id like to see if we can tell where the failure initiated.
slammedmind 9/19/2014 1:01am
9/19/2014 1:01am
Looks like that bikes well looked after.......

Ive seen this happen on all brands of bikes, usually play in the bearings or a loose nut/bolt.
lumpy790
Profile picture for user lumpy790
Posts
11543
Joined
9/18/2007
Location
York, SC, USA
lumpy790 9/23/2014 3:30pm
9/23/2014 3:30pm Edited Date/Time 9/23/2014 3:31pm
privateerconnection wrote:
By looking at the condition of the bolt I am gonna take a guess that you have never greased the linkage bearings before. Possibly had the...
By looking at the condition of the bolt I am gonna take a guess that you have never greased the linkage bearings before. Possibly had the linkage bearings seize up and the force when you land off a jump has to go somewhere. Just a thought. I have seen this before on a bike that never had the linkage greased. These bikes come from the factory with NO grease in them. The first thing we do with all new bikes is FRAME them and tear them down and build them back up making sure to grease all bearings and lube all bolts and etc.
exactly what I was thinking .... plus the bolt looks worn at the end like it may have been loose.
Markopolo400
Profile picture for user Markopolo400
Posts
1426
Joined
7/24/2012
Location
St. Paul-ish, MN, USA
Markopolo400 9/25/2014 7:12am
9/25/2014 7:12am
No way lack of grease did that.

Manufacturing defect...
Brent
Profile picture for user Brent
Posts
5839
Joined
8/16/2006
Location
Temecula, CA, USA
Brent 9/26/2014 10:34pm
9/26/2014 10:34pm
Look like the threaded end of the bolt is bent - maybe the nut came off, and then the bolt backed out of the link halfway during the ride, until the link hit the bolt and split the casting?

Post a reply to: 2015 KTM 250SX - Snapped linkage arm