jetting help please

[03viper159]

got a 944 unionbay in a moutain max chassis, i have a bog between 4500 and 6800 rpms, thinking i may need to drop the needles or go to a smaller pilot, sled idles and takes off fine which makes me lean more toward needle adjustment. when the bog starts if you go full throttle the sled pulls right out and takes off like a rocket. carbs are 38mm mikuni main jets are now at 410(dealer recommended) with the needles in the middle grooves. i know this is not a lack of fuel midrange because if you choke the engine the bog gets worse.

thanks guys

 

[tomseal6]

I had a problem with an old sled that did the same thing but i dont know if you have the same type of carbs it did. 79 433 exciter, the choke plungers were sticky and gummy which caused it to bog in the mid range when i got on the throttle.