Staffo, your richness is hurting you. If you're on 145's go down to 140's with your present setup or bin those rubbish K&N's and get some decent pods. I use 162 mains in my Bonnie with DNA pods and it runs at around 13:1.
If you drop down to 140 mains that will lean up your mixture in a good percentage of the rev range and put you close to 12.9:1 - 13:1.
Low revs is hard to judge, it depends on how you open the throttle on the dyno. A good dyno guy will open the throttle smoothly and not wack it open.
