'03 Fse 400 Dies when dumping throttle abruptly after high rev.
 

My 400 is up and running again but one of the original problems is still a problem after the rebuild. Whenever I'm at high revs or full throttle and come to an abrupt stop, turn etc where I have to dump the gas it completely loses power like you turned the key off. Once it dies, as soon as you hit the e-start it fires right up and off you go. Only seems to be a problem at moderate to full throttle and then dumping it. If I'm at low to moderate throttle or if I blip it down from high instead of a quick dump it seems fine. Any suggestions? Also an occasional backfire from high to low but from what I understand that is normal?

Get your throttle position sensor checked out for resistance value throughout the operating range to find a flat spot .
It's just a potentiometer for the Management system

Problem Solved
 

Thanks for the help and suggestions. I ended up purchasing the software last summer when the thing was cutting out more often than I was riding. TPS etc. all checked out well. Last summer after long hot rides in hot weather it was dying to the point I coulnd't keep it running even by blipping the throttle when slowing it down or dumping the throttle at a stop. Battery died so I threw it on a charger but was quickly notified by the alarm that it wouldn't accept a charge. Took it to my local battery store and had them test it. Low and behold it had a bad cell. Enough power to crank the engine on a daily basis and run all electrical, but enough low voltage that it reaked havok on the system. At any rate, new battery and problem has dissapeared.

Hey - good news I like easy fixes :) does your 400 start on the button when hot? I have to kick mine at the same time!! I understand its a common problem but I dont know the solution?

Dan

Problems starting with button when hot
 

I haven't had any serious problems starting mine with the button when hot. Occasionaly it will want to kick back against the starter when it gets hot, but that's a matter of going in and updating the starter gears to the '04 worm gear kit which I haven't done. Once I recognized the problem, I'll turn the key off and wait for 10-15 seconds to reset the system and then all is a go. I will likely start kicking it while hitting the button just to preserve my battery life since I got stranded in a canyon last fall because the battery died. We tried to push it, pull it, etc. but without any juice the fuel injection won't feed it.

A lot of guys have had real finicky bikes when cold starting but mine hasn't been a problem. If it's a little slow because it's below freezing, I'll kick it with the button and it comes to life.

Good luck.