took out the 250 today for a real ride for the first time after a new top end. fresh port job on it and it seems to start bogging , then revs a lil bit at idle. let it sit for a moment , fire it up and its fine. its almost like its not getting enough fuel. I've put the zilla petcock on it . it might be electrical though. any ideas?. its a fresh 69mm bore with good porting and a 39mm keihin with a ported rad valve and a k@n. current jetting is 58 pilot and 160 main jet with the needle in it center. it seems to only do it after really hanging it out for a bit then starts bogging under a load .

it seems to only do it after really hanging it out for a bit then starts bogging under a load .

Out of everything you said, this sticks out.

Your float level might need to be adjusted. It sounds like your running the bowl dry "hanging it out".
Does hanging it out mean prolonged wide open throttle?

What temp and altitude thing that sticks out is your pretty lean on the main and fat on the pilot for being ported with that carb if you have a decent pipe.