2012 yz450f dies on jumps

[Jbracer247]

First off thank you for reading my post. I have a 2012 yz450f with approximately 70 hours on it. Never had an issue before. Bike has fmf slip on and tuner since the bike was new. Went to a practice tonight and after about 6 laps the bike died in the air either when I was in the air or on the landing. After doing this twice I decided to exit the track. Went back to truck and took all internal parts out if kill switch. Went to track with smaller jumps and no people to land on me and it did it again on jump landing. Went back to truck and completely unhooked the kill switch. Went back out and it did it again. Fuel tank was full at start of ride. If anyone has had this happen or has any ideas. It does not do it on acceleration or braking. Only on jumps so far. Thank you for reading my post i know it is kinda long.

[DC_Excitement]

fuel pumps are known to fail intermittently on the 2010-13 bikes. the fuel filter mounted on the pump in the tank gets dirty, some people have had luck removing the pump. dissembling/ cleaning it to get more time out of it.

[tomjoens]

I think they have roll over sensors in them might be something to look into.

[Jbracer247]

I'm gonna take the fuel pump apart. I think it was dying on the landing of jumps but can't be completely sure.

[Jbracer247]

The tip sensor is inside the ecu from what I have seen. It is programmed to shut the bike off after 20 seconds inverted.

[WouldsAssassin]

Sounds fuel related. Try the fuel filter suggestion and let us know the outcome.

[Jbracer247]

I will start tearing it down this week. Gonna check all connections and clean and inspect fuel pump and tank. Hope I don't have go buy a new pump. Msrp is 402

[72degrees]

I will start tearing it down this week. Gonna check all connections and clean and inspect fuel pump and tank. Hope I don't have go buy a new pump. Msrp is 402

 

I don't know about the FI YZs but on a KTM the fuel pump connection on the tank only has to pull out a tiny amount to cut the pump. Perhaps the tank is shifting under weight transfer. Worth also checking the tank mounting is secure?

[jnabuurs]

I had the same problem and the the diagnosticeren tool told me the tip over sensor in to the ecu had a fault so I changed the ecu bit it didn,t work so I changed the fueltank ignitioncoil didn,t help also. After changing the stator the probleem was solved. Measuring recistance of the statorcoil was food bit it was the solution.

[Jbracer247]

With the problem being intermittent. Was your resistance reading off the whole time it was running? My bike only acts up when being jumped.

[jnabuurs]

I did not measure the résistance at all temperators bit it started with a eEn Nike and got worse after weeks I t tried to find it for weeks. The diagnostic tool trading saus always kwam sensor. I have rep Nike zo I could switch karts and after all it was the coil in the engine.

[jnabuurs]

The problem occured only on jump landings in deel sand the Nike stopt for a second or two.

[Stu2]

Mine did the same, it was the fuel pump

[jnabuurs]

Oké so the problem can be caused by different parts, good to hear this information.

[Jbracer247]

OK so I took the bike apart to check the resistance on the stator. The manual calls out for the the tester to be in the 10x position and read between .6-.9 the problem is my meter doesn't have that option. The only reading where I got consistent readings was on 2000k on the meter. The meter read 1200

[Jbracer247]

It's so frustrating when the problem is intermittent. Did you check stator or anything else first. Leaning towards fuel pump but hoping was gonna be cheaper fix.

[jnabuurs]

I checked everything and the résistance of the stator was normal so I had to guess. So I decoder to change the stator and the problem was gone.

[Jbracer247]

Does anyone what the conversion would be. 12 ohms on the 20k setting would be what on the 10x meter setting called out in the manual? Do I divide by 2.

[grayracer513]

OK so I took the bike apart to check the resistance on the stator. The manual calls out for the the tester to be in the 10x position and read between .6-.9 the problem is my meter doesn't have that option. The only reading where I got consistent readings was on 2000k on the meter. The meter read 1200

 

However you set the meter, the resistance should be between .6 and .9 Ω.  Setting the meter to 10X would make that show up as 6-9. 

 

Sounds like you are using an older digital meter.  The 200 position is the equivalent of the Rx1 multiplier position.  The 20k is the equivalent of the Rx100 multiplier position. A reading of 12 on the 20K position is 1200 Ω, and way out of range.

[Jbracer247]

OK so update I changed the ignition coil an the spark plug. It was the one that came in the bike new. I took fuel pump out and checked all the connections. One was a little loose so I took it off and crimped the wire down and made it slide on way tighter. Put on new kill switch that had been functioning fine but needed to be replaced due to a tear in the rubber boot of it. Was hoping to ride this weekend but if course it's raining for 5 days straight. We needed the rain though. Hopefully will ride Wednesday and will see how it is. If that doesn't fix it will have to decide between replacing the fuel pump or the stator. I found the proper meter but of course it is broken when it was loaned to me. Wish me luck lol thanks for all the help cross your fingers. I'll keep you guys posted.