2011 YZ450F Wont Start...No fuel?

Hey everyone.  Im helping a friend get his bike going again.  He was at the sand dunes and it started knocking really bad, but it was only ideling when it occured.  Took it to a large dealership and they said the timing jumped and  it would be $2,000 to fix due to "evidence of wear" on the lower timing chain gear on the crank.  We picked up the bike and decided to have a look and the gear is fine.  We removed the head and had a machine shop check the valves and do a leak down to ensure valves were ok.  Everything check out with flying colors.  We got a head gasket, timing chain, and tensioner and put it back together per the manual (not my first valve/top end job).  The bike wont fire at all.  It has spark (pulled plug and can see a good blue spark), disconnected the fuel line and kicked it and fuel is pumping.  We cant smell fuel and i tried to look/feel inside the throttle body to see if the injector is working and it does not appear to be doing anything.  After kicking it 50 times i would assume that the plug would be soaked with fuel, but its dry every time.  We attached some power to the injector and can hear it "click".  Im at a loss as to what is the problem.  Any suggestions?  Thanks.

Is the injector receiving a good signal from the controller? Don't know the specifics for your bike but there's nearly always a voltage range it has to see in order to fire hard enough and quickly enough.

I'm not sure what a "good signal" would be or how to properly check. I'm happy to test if someone can tell me how. One other question, is there any chance the stator could be the issue? The only "electrical " components that we touched was the connection to the fuel pump, the connection for the injector, and the water temp sensor. But all those are just plug and play. The stator was the only other "electrical" related piece that was removed, and we didn't even remove it from the engine cover.

I'm not 100% here man, just offering up ideas. I'm using automotive experience here. The specific electrical tolerances would either be in the service manual, manufactures or part manufacturer's websites possibly or surely somewhere on the web. Its a machine so if you dead end then you go to beginning of system and track it to the failure. Good luck, definitely following along.

Don't power up your injector that way unless you're using a very limited power source, like a small 6-9v battery.  Risky. 


Apply a 9-12v DC source to the power feed to the fuel pump to see if it runs.  You can also detach the fuel line from the pump, route a hose from there to a safe catch can, and kick a couple of times with the entire electrical system connected.  It should discharge fuel.  If not, the pump may either have actually failed, or the built-in filter may be plugged up.  It's an exceptionally fine filter, so it doesn't have to be buried in mud to get blocked.  The filter isn't "serviceable", but there's a take apart write up in this forum that covers the process of removing and cleaning it.  Use the search function, and/or browse Common Threads in the index.


Down the list on the second page of Common Threads you'll find links to legal free downloads of genuine Yamaha manuals.  Get one.  Also, either buy or get access to a GYT-R tuner or the shop diagnostic tool and see if there is a stored code in the ECU that might help trace down the problem.


I don't know if one could be made to help or not, but in the automotive world there is a gizmo called a "noid light".  It's a small test light specifically for checking the signal to the injector, and under normal circumstances, the light should flicker on and off while cranking the engine.

Thanks for the reply.  The fuel pump does discharge fuel when the fuel line is disconnected and the bike is kicked.

Hi,I know this is a bit late but I have a 2011 yz450f here in Australia that has been sitting on the stand for 8-10 months with stabilized  98oct.
Went to start it yesterday and it was dead no firing no fuel smell at exhaust. I went the whole starting procedure about 5 or six times and tried a couple of roll starts...nothing.
Hit the web and read this thread,looked at fuel pumps read a buttload of stuff because this is my first FI bike.
Anyway I pulled the spark plug and there was spark...check,disconected the fuel line kicked it and there was a flow there,bugger all but it did pump...check.
Made sure I had a fire extinguisher at arms length got an old suringe for the dogs medicine and got 20 ml of 98 and squirted as deep down the throat of the injector.
First 4 kicks I got 1 second run then the same 2 more 3rd time the beast roared into life and ran perfectly and I was looking at $500 dollar pumps and god knows what,hope this helps someone.

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