Tnt Help!!!!!

[Seed]

Hey Terry,

I need your engineering help. I just brought my new KTM 450 SX home and noticed today when I was out tinkering in the garage that the handle bar bridge was tightened a tad too much from factory. So I was wondering if you would tell me if its still safe to ride until I get my new part that maybe on back order I'll find out tomarrow. Here's a picture. by the looks of it I dunno if the points that are cracked are the heavier load points. So I need your expertice please.

http://i30.tinypic.com/24x2l5k.jpg

http://i26.tinypic.com/24zkd21.jpg

Thanks,
Kevin

[TNT]

Wow! Now that’s an interesting one. What happened is the aluminum clamp failed as a result of compression load (pushing) from the bolt head(as you said from tightening), the failure occurred on the bracket in tension (pulling apart) or a crack.

Either the bolt counterbore depth is too deep or the grade/temper of the aluminum wrong, however I would think they used 2024-T6 it’s fairly good in compression-tension but who knows.

I’d tell you to stop drill the crack but the reason I am not confident with that is you’d be drilling into the counterbore which could propagate a tension crack in that direction and lead to ultimate failure and you’d be drilling right into where the load is the greatest the fastener’s (bolt). This joint on the quad takes/reacts A LOT of load transfer so my answer is no, it’s not safe!

If I were you I’d go to the KTM forums with these pics and ask if this is a common occurrence, if not you can assume you got a bad part (maybe the raw material on the lot was bad) and there are a few like this out there then R&R w/stock (but I’m warning you some of their wall thicknesses look awefully thin to me for alum)….. If it is a common occurrence than I’d look for a steel or TI aftermarket replacement, I’d be leaning more towards the latter (after-market).

Hope that helps,

Sorry to hear this happen to your new quad….Just goes to show Can’s are not the only ones with design-manufacturing issues.

[Seed]

From what I've seen this is the first one I've seen that has come up. Would I be ok to do some light riding for some break in riding you think? I'll be staying away from jumps and other high load situations I'll just stick to trails for now until I get the part. Do you think that would be ok heres a blown up on how everything mounts togeather. there is a bolt that actually bolts into the steering stem in the front of hand bar bridge that would transfer some of the load into the steering stem by the looks of it. Item 17 is the part that is cracked.


http://i25.tinypic.com/30xheec.gif

[TNT]

I'm at work right now give me a little while I got another structural problem on a aircraft I got to solve right now lol...be back soon. Let me study the diagram I'll be up late and give you an answer by morning.

[TNT]

Ok now I got a better pic, the set screw 15 you’re referring to is helping take out the torsion load from our cracked part 17 you’re correct in shear, if that screw fails it will shear off. Fail sequence of events here I think will be a crack through the upper counterbore and we loose that upper bolt bearing area or some of it, but I think we’d retain the lower bolt and we can only hope it is enough to sustain the set screw 15 from failing in shear.

1. I’d stop drill the crack at both ends with like a 1/8 drill to the depth of the crack or a little further.
2. I’d make sure the lower bolt is as tight as possible without further cracking the part and the upper bolt is snug only.
3. Make sure the set screw 15 is tight.
4. Take it easy don’t ride in areas that jolt the bars a lot.

You could drive another self taping set screw like 15 in the rear of 17, same size as 15, the small hole will not do anything to your steering stem since it’s clamped when you get the new 17 as far as degrading it structurally but I’ll leave that up to you.

I know you're anxious to ride just keep your eye on it and be careful,

Good luck!

[Seed]

Thanks Terry. I guess this is not the first case for otheres have experienced this also. So, I am taking it to the next level and contacting KTM as others on another forum are also. For this issue needs to be addressed, for it could cause a very serious injury or death. So hopefully they re-engineer this and initiate a recall for this issue.

[TNT]

I showed this to my coliege he noticed some cracks I missed. We both agree now this thing is not safe.

[Seed]

Yes there is a total of 4 cracks. 1 by the stem and the others on the sides of the counter bores for the bolts. They are on back order till the 26th so 4 days. Not to bad. But this will be a temporary fix until I buy a entire welded chromoly houser steering stem. That way there is no worries because the bar bridge is welded to the actual stem rather than bolted. Which I find that bolting on the actual bar bridge is retarded. Oh well just goes to show every quad can be improved some where.