New camshafts, valve springs and valve retainers needed to fix the 2011 ZX-10R will not alter the bike's 197bhp performance, say Kawasaki.
A Kawasaki spokesman told MCN the claimed maximum power figure of 197bhp will remain unchanged despite major engine modifications needed to remedy a fault which provoked a worldwide recall.
What is spring surge?
This phenomenon is caused by valve springs resonating at certain frequencies, creating inconsistent force on the valve which can then bounce when it hits the valve seat. The bounce means the combustion chamber is not sealed properly, which can cause inefficiency and - possibly - failure. Kawasaki's cure is to alter three significant elements in the spring surge equation: the spring, the cam and the retainer. Because of the myriad permutations these changes create, it is entirely plausible the modification could would not affect maximum top end power.
MCN readers praise Kawasaki
Most users of motorcyclenews.com seemed impressed by Kawasaki's solution to the engine performance problem, with only a few criticising the company for the mistake.
"Glad they came clean and it has re-booted my confidence again."
"I thought this bike was supposed to be "race focused" Doesn't that mean that it will be run at high rpm? To have to fit new modified camshafts/valve springs etc to correct a fault on a bile that has already been released for sale doesn't sound very confidence inspiring. Time will tell I guess but not a very good advert for Kawasaki."
"Kawasaki get a big thumbs up from me for identifying the problem quickly and providing an appropriate solution with the speed I would expect from a top engineering company."
"Fair dues to Kwak for being open about this... at the end of the day it's a 1000cc road bike that revs like a 600 from a few years back."