Aprilia Connecting Rod Recall

Panic and Desperation! That is, if you own one of a particular group of 335 of Aprilia's RSV4 streetbike. It seems that a straightening operation performed on the machine's connecting-rods has in some cases created stresses that could lead to failure of the rod. According to the bulletin on the National Highway Transportation Safety Association website, this could lead to "loss of vehicle control, resulting in a crash, personal injury, or death". The recall program is to begin on or about February 28, 2010, and owners may contact Piaggio (the parent company) at 212-380-4431.

My thought is that quite a bit of straightening must have been necessary, because a great many industrial processes involve cold-bending as a means of straightening a manufactured product. Some of these are con-rods, motorcycle chassis, crankshafts, auto and truck steel driveshafts and gun barrels. It is because thousands of such minor straightening operations are performed daily around the world—safely performed—that I suspect the problem is not so much the straightening as the amount of straightening required in this case.

Manufacturing process such as forging, heat-treating, welding, and surface-hardening often result in small distortions that are normally dealt with by cold straightening. But in this case the NHTSA bulletin says, "This process introduced stresses into the rods which greatly affected strength and reliability."

The smooth functioning of our high-tech world depends on myriad unseen quality control systems. Occasionally something gets through the systems undetected.

—Kevin Cameron

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