1. Get specific info for the '90. I think the 'not removeable' part is true for the 'H' models...but that's not what you have.
2. re: peeing. When? If it's a 'when on the kickstand' issue, then you likely don't have a needle/valve problem, but a float level issue. Note I say ISSUE and not PROBLEM, as it's common for the kdx to 'pee' when it's on the stand even when the float level is set to spec. Set the float level 1mm or so lower and you won't have nearly the problem you do now (assuming that currently it's correct). Besides, that will have the overall effect of leaning things a bit, and most every kdx in the world could use summa that.
You do that by bending the TANG that activates the needle (if your tang is metal), NOT by bending the floats. I'm sure you know that, but I've read the 'bend the float' idea more'n once. It's not the way to do it.