Jetting ?

Been working on my 72' WR250 w/Mikuni 34mm, it had some air leaks etc. I have all that cured and it runs good except a little bog just off idle but only when hot. Let it sit a little and no bog. I think changing the pilot jet would help but which way, larger or smaller? Any other ideas? Seems to be fine once on the needle and main jet. Plug is chocolate brown

For a 0 to 1/8th throttle bog you're on the right track with fixing air leaks and considering the pilot jet. Make sure pilot jet is clean as well as the tiny circuit from the pilot to the venturi. Use a stiff bristle from a wire brush and compressed air to clean.

Keep in mind that the air mix screw should be about 1-1/4 to 1-3/4 turns from the bottom. If it will not rev smoothly at this adjustment then try a pilot the next size or two larger.

Had a 45 pilot, went and got a 50, 52.5 & 60 going to try the 52.5 first. Carb is clean

im thinking its rich off the pilot as its only when its hot that it bogs. cooling down and it likes a bit more fuel. maybe a bigger cutaway to let a little more air of idle . try the 52.5 and if its all blubby then you should know where your at

Where does the balance screw end up turn wise? Sometimes it can be so far off it may take two or three try's to get the balance right. We end up balancing it, turning the idle down, balance it again, maybe change the jet if the balance screw isn't within the specs.
With a bog off idle try pulling the needle up one slot to see if it's a lean or rich bog. If it responds better it's a lean bog.

Alright, I put the 52.5 in, seems to have cured the bog so far, air screw 1&1/2 turns out. Running pretty freekin good now, hoping to be done so I can blue locktite everything, had it apart a dozen times LOL.

great news. jetting is trial and error as long as the error isn't a seizure!

Can anyone list the main, pilot, slide jets for a 1973 250 with a 34mm mikuni conversion. Thank you