12 450 bogged down then stalled after jump

[oldhack]

Hi all I have an issue I would like to share/get some advice on if possible.

On Sunday I hit an 80ft jump 4th gear tapped and when I landed I rolled the throttle on and it just bogged down and wouldn't accelerate. I rolled on and off the throttle a few times and at the next corner I pulled the clutch in and it stalled. It was like on a carb bike when you forget to turn the fuel on and it starves for fuel.

I had a quick look over the bike, kicked it and it started first time. Revved freely and I rode off without further incident. Probably did another 20 laps without a re-of occourance but it made me nervous every jump wondering if it will happen again. The bike has 20hrs on it and I had just fitted a slip on muffler that day. I had probably ridden 10-15 laps prior to this happening and had just topped up the fuel. I am going to pull the tank and check for debris this weekend but failing that I am at a loss on what to check, look for etc. any thoughts?

[Severing400ex]

Check you jetting bud. That's probably why it could be. Or if its a electronic fuel injected its def needs a programmer on it for the new pipe.

[oldhack]

Yeah I forgot to mention that I filter the fuel going into the tank.

It is a 12 so it is fuel injected.

I would have thought the ECU would learn that the motor can breathe more freely now when it was started and left to idle for a few mins prior to being ridden off?

The bike was running waaaay better with the muffler fitted than with the standard setup and even after this incident happened it continued to do so.

Maybe I should put the tuner on it and check for fault codes? I doubt there will be any though as it is back running fine now.

Oldhack

[moto278]

This happened on my 10 while i had it. Try pulling the fuel pump from the tank and cleaning it. Of it happens again after that you need a new pump unfortunately

[oldhack]

Does anyone know if these have a fuel filter at all? Seems like the likley place to start?

[oldhack]

So I take it the only advise is to try cleaning the fuel pump? There is definitely no filter anywhere? I will put my tuner on it and see if there are any codes.

No other thoughts out there at all?

Thanks in advance.

Oldhack

[grayracer513]

The pump has filtration built into it.

[Stu2]

Had the same problem on my 11, but I race offroad so not many big jumps, but it did it when I lifted the front high over whoops or when I wheelied the bike,

Turned out to be the fuel pump, I replaced it and the problem was gone, costly but it cured it,

just to let you know it would be fine on flat ground, no problems, only as soon as I lifted the front, especially when the tank was low on gas

[oldhack]

Thanks guys. Looks like I will be checking/cleaning the tank and pump before my next ride. It's weird it only happened that 1 time so far. I would have thought it might be intermittent if it was a blockage or pump issues. Anyway I will do that and see what happens. Our season starts in 4 weeks so I need it right before then!

[grayracer513]

There have been a couple of reported occurrences of the pump being sensitive to hard impacts from landing jumps and such.

[oldhack]

Ahh good info Grey. Is there any potential fix for this? Maybe support the pump a bit better or something? I guess if I didn't pull in the clutch it may have cleared? I did go atleast 100M before doing so. I thought I would have cleared before then. I looked up a new pump and its $315 US so not cheap to go down the replacement path!

On another note is it ok to put injector cleaner through these pumps? Thought I might do that as well.

Thanks everyone for your replys/assistance.

Oldhack.

[grayracer513]

The only fix is to change the pump. It's an MX bike, and the rumor is that MX bikes do that sort of thing under normal circumstances, so you sort of assume that the components are intended to be capable of it. Apparently, there were a small number that weren't.