Yamaha YZF-R6

Yamaha's YZF-R6 is a 600 cc (37 cu in) sport bike, first introduced in 1999, updated in 2001, 2003, 2006, 2008 and revised in the years in between.

In 2006, Yamaha advertised that the R6 had a redline of 17500 rpm. This is 2000 rpm higher than the previous R6 model and was the highest tachometer redline of any 2006 production four-stroke motorcycle engine.[citation needed]

Hypothetically, if it was the actual engine RPM, it would be at levels previously known only in Formula One engines, where valve spring stress problems led to the adoption of pneumatic valve actuation to handle more than 19,000 rpm.[1]

It was widely reported[by whom?] that the 2006 YZF-R6's motor did not actually have this engine rpm redline level and was closer to around 16,200 rpm, but because of a deliberate tachometer error of about 8%, it read 17,500 rpm on the tachometer. 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,[2] and offered to buy back any R6 if the customer was unhappy.[3]