'14 YZ450F Random stalling = crash

I have a 2014 YZ 450 with 14 hrs on it, it is all stock with the MXA richer map . A few weeks ago, (at around the 10 hour point of total bike ride time, bike still near new), the bike stalled just at the base of a third gear jump face and spit me off, needless to say it was an ugly crash. It had occasionally been popping and farting but this was the first time it actually died momentarily. I thought this crash was just an bad fluke, so I repaired the crash damage and iced my knees hoping for better luck the next time. Well it has now done the same thing 3 more times...unexpectedly stalling resulting in a crash. Expect for these random stalls the bike starts & runs great. As you can understand this has totally ruined my confidence with the bike.

I  run clean 94 octane gas and maintain the air filter and engine oil religiously.

 Anyone else had the same experience with the 14 YZ450? With the complexity of these new machines, can anyone offer some incite as to which FI or ignition component and/or parts could be defective causing this issue. I really need help with this.

I would check for a chaffed wire that maybe shorting when all the weight comes on the bike at the face of the jump.

hmm something poped up here a while back about this same thing. I Think that op was worried about water getting to the gas after washing, i would try talking to them as i believe his 14 just grew out of it, or he did something to it...but dont feel alone on this one its happening accross the country 




not exacley the same but something to start with he replaced the Intake "Pressure" Sensor.

Edited by ekulb14

Also check the fuel pump, mine cut out as soon as the front wheel was a foot above horizontal, was scary

Thanks for the suggestions so far, I will check out the intake pressure sensor and fuel pump.  "Stu2" can you elaborate a bit on how your bike was acting and what you did to the fuel pump.


I never had trouble on jumps but sometimes when I went to start my bike it just wouldn't start, or it would start and cut out a couple seconds/minutes later. We finally found out it was a bad killswitch from a crash I had had a while back. Try disconnecting your killswitch and see if that works.

"Swaldrop", my situation is just slightly different in that the "Cutting out" or monetary stall is occurring on the face or take off of jumps that DO NOT need much throttle, where I'm carrying enough speed to clear the back side and I need to suck up the take off a bit. This has happened twice on the same jump on two different days, plus a mid air stall at low speed and a stall getting on the gas existing a tight bowl turn. All lead to tip overs or crashes. Like you, I'm scared to ride it when it cuts out a random times.

I set the idle at 2200 rpm, so slightly faster then the manual suggests. Since the bike runs great other the the occasional stall, can this really be a fuel pump or kill switch issue? After checking, my fuel pump and gas tank appear to be spotless. 

I never really determined what it was. I ended up going back to a more standard map and cranked up the idle a bit and haven't really had any problems since. Bike runs great now.

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