Can I ask if the float height is 20mm or...

Jesta wrote:I have no idea as the bikes not mine, i saw gsxr400rm on the frame if that helps, adjusting the floats sorted the problem, the bandit manual says 14.6mm for the floats but thats not possible on the gsxr, i set mine as close to 16mm as i could, and it started up after a few seconds on the starter button!

...will this work? I'm thinking 20mm but then I don't know

If we're talking GK76 then it should be 20mm as per Tony Sleep's carb page

20mm seems about right, it does affect how the bike pulls from 2-4K, it's a bit trial and error though, depends on mods if any...
mine runs a K&N with stock headers and sometimes a 'pipe and I've got mine set to about 21.5 with 110 mainjets (I think....) and I've lost some of the clean pull from low rpm so need resetting to 20 or 20.5....never ending carb setup!
The main thing is to make sure they are ALL set to the same height (seems obvious...lol) otherwise you'll never get it anywhere near perfect...

wot i did with mine that hadnt run for over 12 months i knew it was sparkin fuel in bowls jus didnt seem to be gettin through was pulled the air filter stubs off back of carbs and squirted some petrol through all 4 carbs (just a squirt)fired up straight away can leave it a week now an still fires up straight away i usually start it every coulple of days though just to annoy the neighbours lol paul