10 450 cutting out

well tonight nothin scary happend. but coming into a corner, not goin fast, clutch was pulled in. it was idling as i came into the corner. right after i turned around and went to get on the gas... it dies. bump starts right away. ive had this problem before. and read of others on here who had this problem before too. i was thinking. could i have a worn oring seal on the fuel pump possibly letting air by? theres no fuel leaking or nething, but just a thought

The fuel pump pressurizes the system, if there was a leak you would have gas leaking out for sure.

If you were going slow enough and pulled the clutch in sometimes the bike will stall, I find this alot when doing the technical stuff for woods riding. Turning up the idle helps bigtime.

i have the idle set at 1950-2000rpm according to the tuner. should i set it higher?

I found 2000-2200 rpm helped me from stalling when the clutch was pulled in quickly and the bike was coming to a quick stop.

I know this may sounds stupid, but we should rule out the stupid just to be sure. Your not applying the rear brake in the corners without holding in the clutch are you? :smirk:

ill pay closer today possibly. i do both so close together. i do usually us front brake tho

i turned the idle up to about 2200-2350, hate that it bounces around so much on the tuner. seems to work alot better. also rode again with the kill switch disconnected. bogged once, never again tho. i keep the tank full on the mx/sx track but on hills and st i let it go down lower. one other thing i changed was i ran out of vp u4.2/4.4 and switched to 92 pump gas. im not a pro, i only like the race gas for smell and fact it keeps the motor cleaner internally. oh, i did return mapping back to stock, from the jay marmount map. im really confused. ill be riding more thursday. busy week til then tho. any other input from anyone?

my 2006 yz450f started blubbering when hot, especially over the choppy sections. I ripped the vent hose and check valve off and gas started spewing out as though it was bioling or pressurized. I put the hose on sans the valvem and viola. Rode the second half of race with no blubbering.

My buddy has a brand new 2011 with no hours on it. He kick started and while it was running (not long after) gave it a little gas and the bike cut off. I'm wondering if he has the same issue as you. He has the bike at home and probably wont ride until April or May, I'm wondering if he should take it back to the dealer of if it did this b/c maybe the bike wasn't warmed up enough. What you guys think.

Moto I'm not trying to high jack your thread but I feel his problem is similar to yours

My buddy has a brand new 2011 with no hours on it. He kick started and while it was running (not long after) gave it a little gas and the bike cut off. I'm wondering if he has the same issue as you. He has the bike at home and probably wont ride until April or May, I'm wondering if he should take it back to the dealer of if it did this b/c maybe the bike wasn't warmed up enough. What you guys think.

Moto I'm not trying to high jack your thread but I feel his problem is similar to yours

Did it start back up? If it still runs it likely does not have a problem. Just because they are fuel infected doesn't mean they won't stall. The system these bikes are using is not as advanced as the cars and trucks these days so it will not act the same just because the wording is the same as the cars.

i replaced my kill switch and the large o ring at the base of the fuel pump..pulled off while ago to clean and when i had put it back on it didnt fit perfect on there, and when it sat for a couple months due to it being winter i realized there was a slight fuel leak under the tank. so i replaced the oring. and was at the sandbox all weekend in WI and zero problems other than it bogged a lil bit and was cause i was really low on fuel.

Did it start back up? If it still runs it likely does not have a problem. Just because they are fuel infected doesn't mean they won't stall. The system these bikes are using is not as advanced as the cars and trucks these days so it will not act the same just because the wording is the same as the cars.

Yes it did

I have a 2010 that had about 50 hours on it and did the same thing...it would totally cut out and die...then i would move the bike around and it would fire right back up. IT was my kill button...unplugged the button and it never happened again. I have a new button in my garage now i just have to put it on

ok so im diggin up this old thread i started. so my bike is now no longer cutting out. but today it developed a bog after i started riding for about 30 minutes. the tank was full, ive been extremely picky on keeping the tank full since my lil incident last summer. anyways, ive replaced the large o-ring around the base of the fuel pump, i have replaced the kill switch. the only things that have changed with the bike since last summer when it was running great again, are i switched to a K&N air filter, drilled some holes in the air box to breath better, and of course the pc full system. now from what ive been reading on here lately and doing more digging the bike is rich possibly really rich from the factory. could my bog be caused from being TOO lean with my mods? ive been running the stock map since my crash last year where it cut out. but i really did like the jay marmount map? is that richer than stock? as far as weather goes, it was only about 40 F and really windy. so overal pretty chilly. could that be another reason? yesturday was in the 50s with little wind so a very nice for riding and my bike ran perfect.

I've heard a lot about the fuel pumps going out on the CRF 450s 09-10. I guess the injectors get clogged sometimes as well. Had a similar problem on my 09 CRF.

So far I have not read any posts about bad injectors or pumps on the YZ. There was a point where an injector was labeled the culprit in which there was a gas smell in the oil, but that was ruled out.

The jay marmot map leans the bike out, the stock map is rather rich, even if you have a couple mods like a pipe etc.

I really doubt it's your map, especially since you are running the stock one.

tomoro im once again gona pull the airbox, injector and throttlebody off and clean up again. do these things really need to be cleaned that much? or am i just doin somethin wrong? i run vp's u4.4 so should i be emptying the tank after each ride even if i ride every day? i think i read somewhere that its a good idea... but that coulda been for solving the 'gas in oil problem'...if it persists i may just ditch the kill switch all together, with it disconnected it had only ever bogged down once

Did you ever map the bike for everything you have done to it?? Just wondering as I had a similar problem with a friends 10' YZF after adding alot of "extras". He had the EFI and Timing adjusted properly and it has been perfect since. (You mentioned the race gas I think is why I bring it up)

only mapping ive done is the jay marmount map. thought bout goin back to it, or tryin a different map from on here

With the mods and fuel you run I would try different maps to see how it reacts. I may be just a jetting/timing issue as every bike is a little different stock, so adding mods just makes it more unique.

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