Vintage Dirt Bike Q & A

Hey all. I posted earlier about a found MR250. I have gone over a lot of it and am putting it slowly back together. I have taken apart the carb (keihin) and I have cleaned it out and I had to get some replacement jets for it just to get it back to what I think is original. Well today I hooked it all up and turned on the gas petcock and after the bowl filled it just drained out the overflow. I fiddled around with the float height but I could not get it to stop draining. I followed the original manuals instructions on holding the carb vertical and setting the floats to 20mm. Well vertical threw me for a loop, I always thought you had the carb upside down to set the float correctly? Anyway I monkied around with it but could not get it to stop. So started to think that the main float and valve are worn out and do not top the flow. Am I on the right track or is there somewhere els I should be looking? I believe the main float valve and plunger are original. Any help would be appreciated. Thanks!!