Yamaha YZF R6

In 2006, Yamaha advertised that the YZF-R6 had a redline of 17,500+ rpm. This is 2000 rpm higher than the previous R6 model and it was the highest tachometer redline of any 2006 production four-stroke motorcycle engine.

If it was actual Yamaha engine rpm, it would be near rpm levels known only in Formula One engines, where valve spring stress problems lead to the adoption of pneumatic valve actuation to handle more than 19,000 rpm.

It was widely reported that the 2006 YZF-R6's motor did not have this engine rpm redline level and was closer to around 16,200 engine rpm, but because of a deliberate tachometer error of about 9%, it read 17,500 tachometer rpm. In February 2006, Yamaha admitted the bike's true engine redline was more than 1,000 rpm lower than displayed on the tachometer than advertised, and offered to buy back any R6 if the customer was unhappy. According to general legend, nobody sold their bikes back to Yamaha.