Problems with new pipe

[howshnazy]

I recently bought an HMF slip on for my 400ex. Besides the slip on, it has a KNN intake. The person I buoght the pipe from told me to run a 155 main and 42 pilot jet. Well i was already running a 155 main and a 38 pilot. When i put my pipe on and still had the 38 pilot it was running ok. When i switched to the 42 pilot today, it didnt want to start and i nearly killed the battery trying. I started it from a rolling start and kept the engine going by giving it a little gas. I played with the idle screw to get it idling ok, then i let it sit and idle for a while. Then a minute or so later it just shut off and did the same thing where it wouldnt start. Whats the deal?

[2004exrider]

hopefully this helps some, but when you put the 42 pilot in are you pumping the gas 3 times then holding the throttle open a little and starting it and feathering it till it starts idling good? ive had nothing but good luck with mine.:confused:

Jimmy

[ommkevin]

you might be running too rich and when you hit the gas too much gas is getting into the carb and it bogs and shuts off

[tater_kamik]

if it was running fine with the 38 pilot, throw that back in your carb