11' Yz 450 fuel pump problem?

13 replies to this topic
  • Stu2

Posted February 12, 2012 - 09:14 PM


Hi guys, I have a problem with my fuel pump I think, when the bike has about 2 liters left in the tank and I lift the front wheel while hard on the gas it dies and I almost go over the bars,

Is the fuel pump temporarily running dry ? I have had the bike for a few months and never noticed it before, any ideas?

  • GuiF1

Posted February 13, 2012 - 09:44 AM


Yes, you should check your pump and also your ECU inclination sensor. If it is reading wrong it may be cutting the signal to the ignition coil.

  • Stu2

Posted February 13, 2012 - 10:54 AM


Thanks GuiF1, I will look into it

  • Stu2

Posted March 11, 2012 - 08:52 AM


So I took the bike to my mechanic and he said he could not find anything wrong with the bike,

Would the gytr tuner show an error code if this was happening?

Its still happening after about 60 to 70km of riding so the tank is almost empty but it did not do this when I first got the bike so the problem has 'developed'

Any Ideas?

  • grayracer513

Posted March 11, 2012 - 04:46 PM


EFI cars have baffling in the fuel tank to hold fuel near the pump inlet when the level is low. Not sure what if anything Yamaha has done to address the problem of fuel sloshing away from the pump under those conditions, but it sounds like that's what's happening.

  • poppa

Posted March 11, 2012 - 05:18 PM


2 ltrs is quite a bit, you got elecrical problems. could be the inclination senser, but thats sposed to work left to right i believe to kill the bike after a extened lay down. we havw run out of gas racing and never had the bike stall like that. maybe don't ride the weelie so long???

  • Stu2

Posted March 13, 2012 - 08:14 AM


Just to clarify, it may be less than 2 litres as I have never checked but once it starts this i can ride another 20-30km and it does not run out of gas,

@Grayracer, thats what I was thinking but that would not be a good design on a bike that pitches up often like an dirtbike,

@poppa, its not really a wheelie, its when I lift the fron wheel to clear a whoop or log etc, its not a bog, the bike will accelerate or run smooth then cut out completely from fuel starvation,

Its back at the mechanic now, hopefully he finds something, last chance saloon is replacing the fuel pump......ouch

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • iveyyam450f

Posted April 25, 2012 - 12:36 PM


Did you ever find the problem with the bike. My 10' did a similar problem this weekend. I was going up a slight up hill sand roller section and the bike acted like it ran out of gas and almost thru me over the bars. I pulled off the track road it all the way back to the pits. I got home and pulled the gas tank to see if it was out of fuel and it had about .75gallons in it.

  • Stu2

Posted April 25, 2012 - 08:59 PM


I replaced the pump and problem solved,

I tried to inspect the old pump but i don't think it comes apart, when I drained the tank to replace the pump it had 1.3 litres left,so it was drfinately not running out,

Expensive fix! It could have either been a faulty pump, or dirt got in and damaged it, I now take extra care when filling the tank from containers etc and will be getting a fine sieve for the neck of the tank to filter out any dirt or paticles

  • grayracer513

Posted April 25, 2012 - 09:51 PM


Research the use of a sieve at the tank. There are issues related to static electricity involved with that, and a spark there during fueling could be, how shall we say, unfortunate.

The pump should have a very fine filter incorporated into it already. A guy I know with an FI KTM says that his has a 10 micron screen on it. That's like .00025".

  • YZF_MXracer71

Posted April 26, 2012 - 02:28 AM


i will keep my carb. :banghead: EFI is nice and i have rode a few bikes equiped with efi. i just cant imagine coming to a tripple and she shuts off up face :thumbsup:

  • luvnoldcars

Posted April 26, 2012 - 04:27 PM


stu2 get a racor filter funnel. this way you can filter your gas. you still have to be carefull that you dont knock dirt into the tank though. it will also take water out of your fuel. i bought one to filter my gas but didnt believe it would seperate water from fuel so i poured water in the funnel and none went through the filter and out the bottom.

  • Stu2

Posted April 28, 2012 - 02:47 AM


Ya, the pump has a fine screen on it which makes me think it was a faulty pump and it was just it's time to go,

And there was no dirt or particles in the tank when I fitted the new one.....

But it's all god now, pulling strong again and no shutting off or cutting out!

Man what a great bike!

  • Catpizza

Posted April 29, 2015 - 06:14 PM


G''day guys, I went for a ride the other day bike was running fine. Got home and went a wash it a couple days later. Started fine but it was running like shit and stalled a few times finally got it running after warming it up for a bit. Just as I went to put into the shed it stalled and won't start again now. I've read a few things on the net saying About peoples fuel pump stuffing up when they've got low fuel, I thought it might of been the spark plug I've since replaced that, the Old plug was quite fouled up. New plugs seems to have spark.
I'm stuck on ideas what else it could be other than fuel pump but I don't really have the money to be buying parts I don't really need.

Cheers for any help

Related Content


The "going back to the other darkside" adventure... by Monk

Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  94 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.