I've never heard anyone say this...but I can definitely vouch for it. Owned my bike since new and valves would go out of spec WAY early, everytime. Average interval for needing adjustment was about 6,000 miles. At 33,000 miles I was all out of room to do anymore adjustments to the stock motor, so I just replaced it.
Camchain made some noise and replacing the cam chain tensioner with a factory one didn't help. Replacing with an aftermarket manual one did. I have heard this could be due to smaller than spec oil passages in the motor affecting the operation of the stock cam chain tensioner. Maybe tied to my needing constant valve adjustments as well? Not sure.
Anyone want to buy a 2006 R6 motor that needs a bit of work to get room to adjust the valves? :laughing
Other than those damn valves, bike was great! New (used) motor doesn't make the same cam chain sounds the first did so I'm hoping all will be more as expected with this one. I'm a couple thousand miles in to it and so far, so good!