2011 kx250f dies on low rpm

[TBC]

Need help with ideas where to start. The bike dies when idleling and sometimes in slow corners. It's a little bit hard to start warm and cold and you have to give a little throttle to start. It's has a new piston, new spark plug, valvs in spec, no air leaks and the TPS is in spec. The problem started before the piston change. Any ideas?

//JT

[spin05]

TPS sensor is bad......

[TBC]

Why do you think the TPS is bad? I´ve tried to disconnect it and the problem is the same. I´ve measured it and it is right on spec. Last time when the TPS was bad the bike didn't start and if i bumpstarted it, it was running very bad but when i disconected the TPS it started and was running fine on low rpm but bad when twisting the throttle. I was thinking it could be one of the other sensor but i don´t know where to start. I have antoher 2011 kx250f and it is a lot more snappier on low rpms.

[spin05]

Cause my bike did the same thing your does. I had the dealer adjust it. I unpplugged and nothing. They get wet and they go bad. Finally one day i was at a weekend race and I got sick of it.My buddy had a parts discount. I had him buy me a new . They are not cheap. I just installed it in the same spot as my old one. Problem solved. Bike ran like a champ ever since.

[TBC]

Okay, so I went to the track the other day and the bike didn't start att all. Called the dealer and ordered a new TPS, installed and adjusted it by the book and the bike didn't start this time either. Please give me som advise where to start looking.

Edited August 23, 2012 by TBC

[dmm698]

timing. problem arrises after new piston was put in. Valves could certainly be in spec but if they are out of time 180 out it will cause the issue. I've found on the 11 with how lame the fly wheel time mark is its easier to pull the whole stator cover off, find the timing mark on the flywheel (it almost looks sharpied on) and get it in the general area of where the timing plug is and then move the crank. I've sat there for 10 minutes before doing 100 freaking revolutions and not catching it come by (turning it at a snails pace at that..)

Coutn the pins on the cam chain to once you think you have it timed up via the dots and tensioned. I forget the number but you cant count the pins out of your owners manual that comes with the bike from the dealer new.. If thats all set make sure that the cams are where they are supposed to be when its at TDC, possible that a cam spun and it ran before but now that your timing it from the dots (which would of moved when it spun) it will be a tooth off....

Edited August 23, 2012 by dmm698

[TBC]

Thanks for your advice. I had the exact problem that you descibed when i changed the piston and I had to take the cover of to find the mark but I am sure it's i the right position. I have ridden the bike för over an hour with the new piston and withe the same problems as before but the next time it went to the track it was impossible to start. Any other ideas please.

[spin05]

Okay, so I went to the track the other day and the bike didn't start att all. Called the dealer and ordered a new TPS, installed and adjusted it by the book and the bike didn't start this time either. Please give me som advise where to start looking.

Earlier you said it didnt idel and died in the corners and a little hard to start. so yea now that you say it wont start at all then no that wouldnt be a TPS. I would go back and check every electrical connector first

Edited August 24, 2012 by spin05

[TBC]

Checked everything again and everything was good, finaly I took the top off and I found that one of the intake valves was stuck. Hope that after changing the valves everthing will be fine.

[spin05]

thats wierd........