*Rear Suspension Arm Failures* PLEASE READ

[Umyaya]

I would not recommend this. If it ain't broke, don't fix it. The scratches are normal, it's the bending that's not. Problem with some custom work is you don't know for sure what the material is, something might not be right.

Just keep an eye on them, I'm at 8400 miles, no sign of any problems, as with most.

Ya. I assume you can order new ones on the Yamaha OEM part site? if they start to crap out...

 

[Danger]

Bring it to a dealer if they do. Yamaha will cover you.

 

[Umyaya]

So I hardened my stock rear shock by 2 clicks yesterday. Bike feels a lot more firm and stable... Guy who owned the bike before was heavier and I dunno why I didn't change it thousands of miles ago. Anyways IF the problem is from the suspension bottoming out... would making the rear shock harder instead of softer be ideal since the softer it is the more it'd bounce on bumps and things!? or is this wrong? Thanks!

Bring it to a dealer if they do. Yamaha will cover you.

 

[Sabis8]

So I hardened my stock rear shock by 2 clicks yesterday. Bike feels a lot more firm and stable... Guy who owned the bike before was heavier and I dunno why I didn't change it thousands of miles ago. Anyways IF the problem is from the suspension bottoming out... would making the rear shock harder instead of softer be ideal since the softer it is the more it'd bounce on bumps and things!? or is this wrong? Thanks!

Yes, stiffening the suspension will help. It won't entirely resolve the problem, would act sort of like a band-aid. Need to remember that the spring rate doesn't change, the bikes are still under sprung for most riders. When you adjust the preload of the spring you're just changing the initial force that causes the spring to compress. Once that ammount of force is reached it's still going to compress as it would have before the adjustment.

 

[Fazer 8]

It's good to know about this issue so that I can keep an eye out for it.

I'm not sure if those links are aluminum or steel, but either way my guess would be that a batch missed getting the proper heat treatment or something like that, leaving the material itself weaker than it should be. It's hard to imagine Yamaha's engineers would have gotten the design wrong, especially with the tools available today, but if the material is not as spec'ed, that could do it.

 

[Marthy]

Yes, stiffening the suspension will help. It won't entirely resolve the problem, would act sort of like a band-aid. Need to remember that the spring rate doesn't change, the bikes are still under sprung for most riders. When you adjust the preload of the spring you're just changing the initial force that causes the spring to compress. Once that ammount of force is reached it's still going to compress as it would have before the adjustment.

Finally someone who know what he's talking about! I do appreciate when it happen...

 

[hlmiskelly]

I'm not sure if those links are aluminum or steel, but either way my guess would be that a batch missed getting the proper heat treatment or something like that, leaving the material itself weaker than it should be. It's hard to imagine Yamaha's engineers would have gotten the design wrong, especially with the tools available today, but if the material is not as spec'ed, that could do it.

Have these failures been tied to one particular year of bike? If these failures are occurring in all model years then it is unlikely to be associated with an improper treatment (many different lots of material would be used over several years) or with a design flaw (would have been fixed following early failures).

 

[Bomber12357]

There is most likely nothing wrong this the material in terms of a defect in the molecular structure. Look at the photos and lets use some physics.
-The best photos here we can see that both supports are bent in the same location, and they are not yielding big pointer.
- yes triangle are strong but this support bracket is intended to transfer 2 dimensional loads. ( with the plane of the bracket)
- to be even more correct these brackets are not bending they are buckling. which means that there is a load in the z dimension.
an example is an egg can support 30 lbs if the weight is perfectly distributed downward if it is not the egg will buckle and crack

i would start by measuring the distance between the 3 connection points and see if the brackets when on the bike are almost perfectly parallel.
there is still a thought that this aluminum maybe inferior the the stress and load applies but that is hard to understand when not knowing what type of aluminum we are dealing with.
and some people are saying that the metal must have some give to it so that is why we are seeing this buckling to the i say what do you think the shocks job is? metal (in this application) is meant to be rigid.

and i know the egos when it comes to riders but please don't assume i am talking out of my ass i AM a Mechanical Engineer yes with a degree
but please do check for this problem i know i an tonight after work.

 

[harry]

Hi,
I know it has been a while since anyone posted but I just noticed the same issue on my bike. I called up Yamaha and asked them if there was a recall and they said no so I am going to change the arms myself. I was wondering if anyone who had this issue had any other damage down there or if that was the extent of it? Any damage to the shock etc?

Many thanks