XB Rear Engine Mount Warning

[konarider94]

Don't get me wrong, I agree it's good to be informed and this post is definitely worth a read. But I'm also a Mechanical Engineer that started as a Machinist. One thing you Cannot predict with exact accuracy, is how metal (especially alloys) will act in the Real World. It's like trying to predict weather or the wave height of a tsunami - there's simply too much information that isn't considered or isn't even yet to be understood.

maybe not exact but its pretty damn close. we have a very good understanding of alloys. its not like the composition of alloys change now, we have a pretty good control over materials. even composites are becoming very well engineered. this is why cars and airplanes are getting lighter every year. its fea programs that help us optimize designs. i too am a ME that started as a machinist. I realize im a young engineer but i also understand the newest technology very well.

[Stevenc150]

I understand that, do failure analysis on a fairly regular basis concerning support structures (automotive door pillar beams and suspension). Thing is we do the stress test, get the nice colored renderings showing likely failure points - then I have it machined/formed and do a "real-world" test and it's different. You cannot account for everything because we don't understand everything.

Edit: Again, yet to see/hear of any rear engine mounts suffering catastrophic failures in the "real world". No matter how much analysis is put forth, until something is physically proven - it remains a theoretical outcome.

[BRatigan]

Will hardening the exterior surfaces through type 2 anodization help with distribution of stress loads? Might make the difference.

BR

[ElliottM]

Again, yet to see/hear of any rear engine mounts suffering catastrophic failures in the "real world". No matter how much analysis is put forth, until something is physically proven - it remains a theoretical outcome.

Unsure if you read above posts, but there have been cases where specifically the rear engine mount has failed catastrophically, which I understand as the part breaking completely off of the engine itself, thus causing riders to crash their bike. So far this failure has only be linked to previous accidents, although the possibility of wheelies eventually causing a similar outcome is there.

[kyle_dewald]

Mine broke in a wreck but didn't break causing a wreck.

[boosted]

Will hardening the exterior surfaces through type 2 anodization help with distribution of stress loads? Might make the difference.

BR

Probably not. The stress concentrations will exist regardless of the surface finish. In addition the Anodiziation will, if anything decrease the tensile strength and fatigue resistance due to micro cracks in the coating.

[BRatigan]

I did not know that. This is another good thread.

BR

[hobby10k]

I hit a pot hole on a trip recently, and the bike started to slightly vibrate more than normal. It seemed different but I wondered if it was just in my mind. I quickly checked over the tires and belt etc when I stopped, nothing out of the ordinary.

well I continued on the trip and one my way back it started to vibrate more. so I stopped to really inspect the bike. Thats when I noticed the rear motor mount was broke off. It seemed like it would be ok to at least get back home if I took it easy, so I took it easy and continued on. After I got home thats when I noticed the front motor mount was broke too!! that could have been very very bad!!

so yeah it is prone to failure and that was just from normal riding, I don't wheelie or race, and have never wrecked the bike.

I will post pictures if anyone is interested.

now I need to find a couple motor mount replacements.

[DualSportDad]

I think we would all be interested in pictures. Also year and model of the bike.

[hobby10k]

I dont know how to get a darn picture to show up...I'll try and get the rear up


front:
http://i30.photobucket.com/albums/c3...ps25ni99s7.jpg