03 yzf 450 stumble????

i pm'd jd asking questions and wanted to post in here v.s the jetting section to get some real world feed back from you guys that own the yzf's. this is driving me bonkers.

i have an 03 yzf450 i ride in michigan 600-1000 feet ele. running 165 main, 45 pilot fuel screw 2-1/4 stock motor no pipe no mods. temps are 50-80. starts cold and warm great, idles fine.... BUT,

i have a funny intermitent stumble, it doesnt do it all the time but i cant figure out when, and why it does it all the time. feels like it is running out of gas, then comes to life. not a rev limiter issue just a funny stumble.

i am running this in supermoto trim and mostly notice it from dropped throttle to picking the throttle up hard to get to the next corner. it doesnt do it all the time and it is driving me NUTS! could the main be sucking the float bowl dry intermitantly? the yamaha snowmobiles did this, and their cure was a deeper reach main jet. i am grabbing at straws now.

any ideas? frustrated.... ski

good catch, can those be taken out for cleaning? or replacement if really bad. i havent checked yet but i am going to give it a shot.

anyone else have suggestions? ski

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