CARBURETTOR Problems In Low RPMs

[7uckyDog]

So did the bike come to you with these problems, or did they develop while you've had it?

It hasn't been idling very well after a rusty tank incident. Carbs have been cleaned, floats leak tested, O rings replaced, and new needle valves fitted. After a lot of struggle adjusting the fuel level it seems to have changed over a period of few months and sometimes the valves don't seem to be closing properly as the level is randomly too high. The new needle valves have a harder spring, bigger rubber needle and the seats have a bigger hole and are marked 2.0 instead of 1.0 like the old ones. Apart from the obvious differences they seem to be same. My logic thinking tells me that a harder spring would make it easier for the floats to close them but maybe I'm wrong. I did a leak test with the bowls off and not a single drop of fuel was spilled. But when adjusting the fuel level I had to bend the tangs on the floats quite a lot towards the valve to be able to obtain a "useable" fuel level.Does anybody have experience of these aftermarket needle valves? Or any other brand? Here's a link http://www.ebay.co.uk/itm/CARBURETTOR-FL...Swqv9V6uV1