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Need help with jetting 03 400ex aftermarket muffler

1K views 6 replies 3 participants last post by  CantFeelMyLegs78 
#1 ·
I just installed a slip on muffler on my 03 400ex and I know I’m running a little lean. Does anyone have any estimates as to what size pilot and main jet I need. I have a stock air box and stock pipe the only thing I’ve changed is the silencer. I think right now I’m running a 148 main and 42 pilot and stock needle height. Any thoughts are much appreciated
 
#5 ·
I noticed it was sluggish with a 160 it bogs when I really put it under load. I’m going to try a 155. What are you running for a pilot? I can’t seem to get mine to idle correctly once I put a 42 back in it it will idle fine for a minute then just die but if I give it throttle and let off the idle revs high and takes about 20 seconds to return to normal
 
#7 ·
We have a 42 pilot in it right now. Fuel screw seemed to like 3 turns out which is pretty rich for idle. Ours is hard to start when cold and won't idle without giving it very little throttle for a couple mins. After a couple mins of warm up, it starts right up without throttle and will idle forever at 1450 rpms
 
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