Carburetor leaking gas out of the overflow after it sits for a while and with the petcock turned off. I adjusted the float hight to where it should be and the needle seems to be alright. I think it is building pressure somewhere but I blew out all the vent tubes on the carb and cleaned it. Also I took the gas cap off and the problem still persist. It’s an all stock 1987 Trx 250r.
Check your float needle and the seat. The needle has rubber on it that can harden and dry out over time. The needle and seat can build up varnish which causes them not to seal.
Also the floats can stick. Make sure the pin is clean and the float can move freely. You can check for leaky floats by tapping the bowl when it's leaking. If it stops, then the float is sticking. I use a ball peen or similar to tap the bowl. Just light taps.
It's a gravity feed system, so the only pressure you should be seeing is pgh. Unless you have an excessive change in temp