crossfireken

I have a 600 efi crossfire, just bought it, and took it out today for the first time, it has 700 miles on it.and everything looks as good as new. But it has a mid range bog in it. after it straightens itself out it goes like crazy. it is in the midrange to top end where it bogs.for just a second. do you need to lube the clutches on these??
I have read about the plug for blended and regular fuel as well could that do it?? or maybe could it be something else. any ideas guys too rich maybe???

thanks for now
Ken