| Author | Message | ||
     1324 |
The bike is a 2003 XB9S with just over 10k miles. Only been the track one and I generally just ride to ride so I don't beat it too much. Anyway, I noticed this today and it has me concerned. It is in an obvious high stress area and falls right on the mold/parting line so the crack is aligned with a notable stress riser. 50% of me feels that the crack is more of a manufacturing defect than it is fatigue crack because of how the crack edges look and the fact the powdercoat appears to be pretty smooth around the crack and possibly even cover the inside.   HOWEVER, I can't tell how deep it goes and a part of me feels like the powdercoating operation would have filled this void in if it actually were a mold defect. Without taking the swingarm off the bike and inspecting, I'm not sure what to think. I may measure the crack and keep an eye on it, but obviously it has me concerned. I'm not a failure analysis expert and I know how aluminum can fatigue, let alone how certain casting grades are susceptible to stress corrosion cracking. Has anyone seen anything like this before? Is it even worth my time to send these pictures to Buell? Even for the hell of it? I know Buell redesigned the swingarms at some point, was this a concern anyone knows about? | ||
| 1324 |
Sorry, I didn't edit the pictures to highlight the area of concern. If you don't see it already, look at the mold line on the shock attachment point, parallel to the bolt. | ||
| Ft_bstrd |
It's gonna be tough to tell without having it x-rayed. It could just be a crack in the powder coating. If you don't want to take it off, you might just see what it looks like after sanding off the coating. That way you can get a good look at the metal. It may not be as bad as you think. I don't think I've heard of one cracking like that. | ||
| Djkaplan |
No way to tell visually, but I doubt that's a stress crack. It looks more like a casting flaw. It doesn't look like it's in an area where it should cause a problem... but definitely keep an eye on it. | ||
| Odinbueller |
It takes a pretty hard crash to crack a swingarm, and our race bike only needed the bosses for the pivot shat bearings touched up, nothing structural. If you're up to heading over to Rahway, we'd be happy to take a look at it for ya. Chris | ||
| Slaughter |
I think to look at it, it's a surface detail and not a crack. I understand your concern but there's just no way to abuse that fitting enough to crack it without destroying other stuff since there's just not that much load going through that point compared to the axle or pivots. I think it's a surface detail left over from the original casting being machined... again, kinda hard to diagnose from the pics. Chris (Odin) is offering... take him up on it! Good to have another set of eyes on the problem. My rear end got torn apart (tore the Penske in half, slammed a hole into the crankcase) and it's re-usable: http://img.villagephotos.com/p/2003-9/403336/15Apr ilcrunch.jpg | ||
| 1324 |
I may make a trip out to Rahway if I get a chance. I do agree that this is probably not the result of regular use or even damage for that matter. I do a lot of work with castings and casting design, so this isn't really new to me. I'm lucky in the sense that the 'crack' is on the side of the attachment that is under compression most of the time. If it were on the other side, it would be in tension and I'd be more concerned. And like I said, I'm pretty sure it isn't a stressed crack because there is no indication of plastic deformation around the edges of the crack. Granted, that is not always an indicator, but this isn't a shocked part, so I'd expect to see some plastic def. Still, I just wanted to see if anyone has ever noticed something like this on their bike in the past. If it hasn't failed in 10k miles, I feel safe that it won't get any worse. Personally though, if my QA guy/gal caught this and it came across my desk to waive or reject, I'd reject it in a heartbeat, especially given the implications of a failure on the road. | ||
| Ponytail |
I'd say it's a casting flaw. If it were a crack, it'd go to the edge of the part. It's much too clean and doesn't have the "trail" of crack, especially of one in a machined casting. If you want to check it out further though, from the minimal job description that you gave, I'm assuming that you have access to a 10x inspection glass, chemical strippers, acid etching kits, and dye penetrant? Easy to do. If you sand the paint off, and it is a crack, there is a good possibility that you will fill the crack with paint/metal debris and basically hide evidence of the crack. At this point, seeing where the suspect area is, I'd ride it and keep an eye on it. If it is a crack, it should develop quickly toward the edge of the part. Mark the ends of the crack with a fine tip perm marker, and just keep an eye on it. The other thing you can do is fill it with white-out or "torque stripe". The white out won't last long at all but should last long enough for a good ride or two. Both can be used as "motion detectors". If the white out or torque stripe cracks, then there is movement (necessary for a crack to grow) and you'd know if you needed to investigate further. HTH (Message edited by Ponytail on August 23, 2007) | ||
| Tdiddy |
Good advice on the white out and torque stripe. |
