So Ive read tony sleeps write up here http://tonysleep.co.uk/gsxr400carbs" onclick="window.open(this.href);return false; and so am gonna be overhauling my carbs (bike wont go above 2k rpm at the mo)

Got the tops off but cant work out how to adjust my float height which varies from about 14-16/7 mm at the mo, supposed to be 20mm.

Can anyone help me as to how to do this? Im pretty new to carbs you see!

You have to gently bend the tang which touches the float needle valve (circled red in the pic showing the float height on Tony's site) to get the correct height, its a bit trial and error to get it correct, it's laborious

thanks got there in the end! Bike still runs crap though

i dont think the float height setting is going to prevent you getting above 2k RPM - try cleaning out the entire bottom half of the carbs, all of them. Most likely some dust/dirt/crud blocking a jet(s).
Check your needle valve too.

Do em 1 at a time, unless your meticulous with your dissassembly/reassembly.

Im not sayin this because i supply them but 90% of the time if it wont run right its the o'rings that are giving trouble, unless its electric that is!

I also agree wit /variable here. The factory orings get minced by the fuel over the years. Replace every oring ya can find! Good luck wit it.