550f running rich?

[DomP]

With this in mind might it be worth trying my needle clip one lower, which on an F will be the last position.?  All of my parts are genuine Keihin and correct for carbs/bike

If you put the clip one groove lower that will raise the needle and make it run richer.

Try going the other way, put the clip one groove higher to lower the needle.

Sorry Gareth thats what I meant to say, its the last clip position so im not going to get any lower than that, im hoping ill have enough range to play with the air screw in this position

[K2-K6]

Dropping the needle will primarily affect the mid range response  .... if that wasn't wrong, it should then produce a flat spot as the throttle opening transitions from low speed into that range.
In effect, you'd be moving the two parts further alway from each other as it'll not change (much) the lowest point metering. Low would stay rich and mid would move toward lean.

If it's definitely rich at low slide opening, then it's usually the idle jets (assuming the others aren't nuts in volume)  and so you'd correct with them by going smaller idles.

Of interest, what absolute vacuum reading is shown on the sync gauges if you use them  ? 

This complexity is why I'd be absolutely sure of cam timing before you begin diagnostics of carbs. If wrong, it'll run you ragged trying to think what you can adjust or the permutations of error ... all in vain too.

[McCabe-Thiele (Ted)]

Are you on the original air intake/ filter system?

[DomP]

All standard except the 500 filter change with a genuine honda one. I purposely have tried to keep it standard to make tuning straightforward....obviously that bit hasn't gone to plan as yet