2014 yz450f cutting out

[Sheetmetalfab]

So riding today my bike ran excellent the first half of the day.
I did add fuel at this point from my MA fuel can.
Then began to cut out at mid and high rpm.

I’m running.
Thermobob
Skid plate and left side full shroud. (Right side half shield)
Radiator block offs in and out to keep temps in check.
160-200* F all day.

The ambient temperature didn’t change. 24-28*F

The fuel in the bike and the can came from the same pump.
Non ethanol 90 octane. (All we get in Alaska)

Has anyone else run into a similar issue with a 14-16 yz450f?

Maybe fuel pump? Filter?

Stator? (I have zero accessories drawing power)

Spark plug? ( I checked that the cap wasn’t loose)

My intake was clear (pre filter covered pod under stock cover)

 

[Sheetmetalfab]

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[dooman92]

Any chance the fuel from MA tank had moisture in it? Run fuel out or add a little isopropyl alcohol? Nice photo btw.

 

[wwillf01]

If it continues to happen later in the ride or after hard pulls my money would be on the fuel pump... Or Injector... Was this ran with wheels in the summer.... Also how old was the fuel used.

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[n16ht5]

Sounds like partially clogged injector

 

[teal_210]

Might check the head pipe for cracks

 

[Sheetmetalfab]

If it continues to happen later in the ride or after hard pulls my money would be on the fuel pump... Or Injector... Was this ran with wheels in the summer.... Also how old was the fuel used.

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I ran it 4 rides with wheels this summer.
Had 1/4 tank when i filled it and the can on our way to ride.

I guess i’ll start with a fuel pump test and injector spray test.

If it is a cracked header pipe that would probably be the easiest fix.
(A good chance to practice my titanium welding.......)

 

[wwillf01]

I ran it 4 rides with wheels this summer.
Had 1/4 tank when i filled it and the can on our way to ride.

I guess i’ll start with a fuel pump test and injector spray test.

If it is a cracked header pipe that would probably be the easiest fix.
(A good chance to practice my titanium welding.......)

I know I had a fuel pump issue... It tested fine but once it started being overworked then it could not keep up... For me sand was in the tank from the previous owner

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[Revv Up]

I'd try fuel filter(s) first

 

[AZ800]

It was actually only doing that because you shouldn't be riding yet! Too early. Try it again in 2 months when the rest of us get snow! Lol

Did you give it a rest and it would still do it? I.e. Let the fuel pump cool down?

 

[Sheetmetalfab]

It was actually only doing that because you shouldn't be riding yet! Too early. Try it again in 2 months when the rest of us get snow! Lol

Did you give it a rest and it would still do it? I.e. Let the fuel pump cool down?

Definitely the earliest I have ridden good snow.

It kept getting worse throughout the day.
After a long break there was no change. (Checking the spark plug boot and head pipe)

 

[Sheetmetalfab]

My brothers wr ran sweet all day.
Stock ecu with the mxa aggressive map.



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[dirtrebel]

Are you sure you weren't getting a frozen filter skin? On my 12 yz I had problems with steam from warm engine creating moisture and freezing my pod style intake skin when stopped to fuel. I ended up using the stock intake boot with a yz specific outerwear in place of the stock foam, then just ran it with no air box lid, no more steam no more problems. Except loud as hell. On my 16fx I run a snorkel that sticks out through a hole in the air box lid, loud as hell but flawless. Anyway I found the engine heat would create a ton of steam under there and then when you go all that cold air rushes in and freezes the skin over, the front intake is kinda a love hate thing for me

 

[Sheetmetalfab]

Are you sure you weren't getting a frozen filter skin? On my 12 yz I had problems with steam from warm engine creating moisture and freezing my pod style intake skin when stopped to fuel. I ended up using the stock intake boot with a yz specific outerwear in place of the stock foam, then just ran it with no air box lid, no more steam no more problems. Except loud as hell. On my 16fx I run a snorkel that sticks out through a hole in the air box lid, loud as hell but flawless. Anyway I found the engine heat would create a ton of steam under there and then when you go all that cold air rushes in and freezes the skin over, the front intake is kinda a love hate thing for me

I pulled that plastic cover a couple times throughout the day (when it was cutting out) and saw zero ice or frost. (Over or under the pre filter)
Was 25-28* F all day.

Pulled the pump and didn’t find any debris in anything.
Spark plug looks pretty old and rallied so i’m Putting a new one in.

Ordered a new fuel pump (because spares are nice if it’s fine)

 

[moonbeam1719]

Few more things to consider....bad ground/power supply..check connections for light and warmers if you have them...air temp sensor in bottom of air box covered in snow/frost causing over fueling of an already over fueled cold engine (there are holes in bottom of the air box that are hard to see..i silconed all except one shut).what does your oil look and smell like?..still no luck check valves and timing...hope you find the issue.

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[snobikr]

Fuel pump or filter?

my 2015 started cutting out when I would get to about 1/2 tank and pointed downhill. When I topped the tank off it continued to work fine until I got back to half tank. Had about 60 snow bike hours on it. I figured it was either the pump or filter. I ended up changing out both the pump and filter because I didn't want to troubleshoot trying just the filter because pulling the pump housing apart was a royal pain! totally fixed my problems though, never had it act up again.

 

[n16ht5]

did you put compressed air through the injector?

 

[Sheetmetalfab]

So i swapped the spark plug and it runs perfect........

Trying the easy things first pays i guess.

 

[Sheetmetalfab]

Today didn’t suck.

Too bad the Timbersled can’t do that.......


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