A new set of CBR600 F4 1999 carbs ran good but rich on under heavy load on my 1.4 AFH head POLO set up. 150 jets. I purposly did it as I knew on the next engine they would be perfect.

So now on my 1.6 set up , same engine AFH but ported and race cam, the carbs run better 13.5 - 14.2 under a decent load.

Only difference I notice was for some reason on feathering the accelerator like a grandad when cruising somet doesnt feel right.

AFR is 11.5. Just felt boggy especially up hill. As soon push down on pedal a litle more, the AFR increases to where it should be and you can feel it's right. As if throttle response sucks!!!!

The ignition map on megajolt is a default one because I couldn't risk using the one I had on the 1.4 setup.

Maybe this is all normal, not sure.

turned out to be intake pipe ducting flange on the air box. it kept popping out one corner but i would not have thought that would result in a richer mixture under light throttle.

if anything would have expected it to be more leaner.