I think its solved now, and it seems it was my own doing ! My bike was fitted with 900 carbs when i bought it, 900 carbs have 1 petrol intake pipe.
I have recently fitted the proper 1100 carbs with 2 petrol intake pipes.
Because i now have 2 intake pipes i needed a T piece. this is were i went wrong, I simply connected the pipes to the T piece wrong.
My fuel pipe from the petrol tap went straight down from the top of the t and out of the bottom into carb 1 & 2. it then fed out sideways to 3&4. I put the t piece the right way round and problem is almost solved. ( only a really small drip from carb 2 with engine off ) tap off solves it.
only time will tell if this was really the problem.