Power charts

Now I've still not got the bike back. I've been advised by the chaps at the garage that as the inlet manifolds are so perished its letting in the air and bogging her down, don't know if that right or wrong but if they are perished then they need replacing anyway. So I'm searching for a set of 4 good rubber inlet manifolds.
It sucks not having a bike to ride but the only saving grace is the fact that its rained every day now.