10 450 cutting out (random STILL)

ok so i have yet to figure this out. altho it has gotten really odd now. it only cuts out at WOT, and is completely random, some days can ride all day without a problem, others 15 minutes and its done. so yesturday i was riding, it happened, plugged the gytr tuner into it, read the computer totally normal. tp is 0, all temps normal, no codes. took off the tuner went riding, didnt have a problem the rest of the day. so after about 20 min of hard mx riding, 2 minutes screwin with the tuner nd went bak out, its completely normal. ive cleaned the fuel pump, injector, tb, tp sensor, checked all my wiring, no exhaust leaks, no air intake leaks. air fliter is clean, fresh oil, fresh gas. runnin vp's c12 for my cp 13.75:1 piston. anyone have any ideas? its driving me insane!

"Cuts out" means shuts off, a regular (rhythmic, has a regular cyclic pattern) miss, or an erratic, irregular misfire?

also have you had this problem in warm temps or only cold? The reason I ask is I had a similar problem one day riding fast in the cold. The fuel mixture was so rich I had an ocassional "miss" and some stall issues.

usually happens when the motor is warmd up. did it during summer and yesturda (50 degrees F) i go to crak the throttle WOT and the rpms climb till the higher rpms (wouldnt do it connected to tuner so not sure at wat rpm it starts) but the motor just stops, rpms drop and right before it dies the rpms pick up again then get high again and same thing opens. thats if i leave the throttle twisted WOT, it doesnt stop, keeps doing it. like i said before, the only time i ever got it to stop was yesturday when i connected my tuner to the bike nd tried to re-create it. didnt happen

I don't think 50 degrees is cold enough to cause what I described. I'd be leanin towards a fuel pump problem. The only way to catch it would be to have a fuel pressure guage installed inline and watch it while problem occurs which isn't ideal.

Sounds like the fuel pump, but it's odd it won't do it with the tuner plugged in. Having it straighten up with the tool connected suggests an ECU.

If you have a friend with a similar bike, you might try swapping components around, otherwise, you're going to need some more advanced diagnosis.

Did you ever figure out the problem? Mine seems to do the same.

Have you checked your kill switch? I had the exact same problem, WOT and it would just completely die. Not cool when you on a night ride and your helmet light battery is almost dead. When I got home I pulled the kill switch apart and it was packed with dirt and mud. The tiny spring that holds the contacts apart was corroded to the point that it was almost non-existant causing the contacts to close slightly and intermittently. I trashed it and got a replacement from Rocky Mountain. Surprisingly, quality was almost as good as oem. It did have the same plug which was a nice bonus and it was only a fraction of what the oem part cost.

For a simple test just unplug your old one, I bet your problem goes away. Just be aware that if you unplug it you'd only have 1 way of shutting off your bike.

change your throttle position sensor

I tried the killed switch and it still occured. What is the reasoning for throwing a TPS at it. Have you had a problem with the TPS on your Yamaha?

i have had to replace one and 2 other people i know have also.

I have the same exact problem on my 2010, I cheched inyector, cables, pump, and its a pain, I´m thinking about selling it and get a 2 smoke, it´s a pain in the ass.

The bike when is running Ok is OWSOME but I dont know what else to do.

Any luck?

" What is the reasoning for throwing a TPS at it. "

i had an issue w/ my 2007 Yamaha Grizzly 700 FI with performance related issue's regarding throttle position. using the "POD", it allow's the tech to look at the voltage of the TPS and it's range's (closed throttle / open throttle). even though the range was within spec, the TPS was still defective.

i changed it out and this thing runs like a scaldded dog. not saying that your TPS is indeed the issue, but maybe try swapping it with a know working TPS.

hope you get this figured out amigo

Thanks, I´m gonna clean my TPS sensor, i just came from my dealer and got a new injector, but they don´t have the TPS. Hope that works

A buddy of mine had his TPS fail as well (2011 yz450), would bog randomly... Swapped his with another one and problem solved.

I guess Ill try a TPS. I removed it and bench tested it and tests fine. I hope it works for the of them.

OK. I bought a new TPS and it did it first ride. It did it in the same place on the track two laps in a row. It occured on a place on the track where I hit a small jump, land WOT into hard kicker. As I land still WOT to go down a straight away, it just falls on its face and almost throws me over the bars. Not fun.

I have the same problem on mine tested everything it feels like sometimes the fuel tank is empty but it isn't and it mostly happens on jump landings the last thing I will try is to connect a pressure tool to the fuel line to see iff the pressure drops because the problem gets worse so it's easier to find.

That sounds like what is occuring on mine. Its also happened in whoops and I think its only at wot. I tried a fuel pressure tester in line and it was always with in specs but I was not able to duplicate the problem with the fuel pressure tester inline. I suspect the lean angle sensor in the cdi is causing the problem. I havent been riden lately but i am going to try to swap my cdi with one of my buddys or possibly buy an aftermarket from Yoshimura or Bazzaz.

Plugged injector......

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