My best time on my R6 in 2015 was 1:23.7 (and I raced that bike for 3 years).
My best time on my R1 in 2016 was 1:22.4 (this was my first year on the 1K).
I found it was easier to put down a faster time on the 1000cc. Even though the bike is a lot more work to ride, I found quicker times came more easily on the 1K.
Except for near the end of the day when conditioning came into play.... I was usually a mess in Superbike due to just flat out being exhausted. My quickest times on my 600 came later in the day and later in my races, and when I got tired on the 600 I could push through it and keep going faster. But on the 1000 I found it more difficult to do so, and I realized after this season that I need to be in much better shape if I want to be competitive on the liter bike.