2009 YZ 250F Start Issues

VetTracker
Posts
76
Joined
4/1/2011
Location
Temecula, CA US
Edited Date/Time 5/18/2016 10:35pm
Hi Guys,

I am having an issue starting my 2009 YZ 250F.

What I have checked so far:

-Gas was completely drained out of the carb and tank, refilled with gas from yesterday
-Pulled the float bowl off of the carb, cleaned main, pilot and the jet in the bottom of the float bowl.
-When the gas is turned on, fuel comes out of the carb drain (when the screw is opened)
-Valve clearances are all within spec
-Visually checked and verified spark
-Accelerator pump appears to be working

It started for about half a second within the first 10 kicks or so, since then the bike doesn't even try and turn over when kicked, nothing when trying to bump start either.

Tried choke on/off, hot start on/off, opened the throttle while kicking.

Here is the strange part, when we pulled the plug to check for spark it was completely dry. I know the fuel is getting to the float, but it doesn't seem to be getting to the engine.

A little history on the bike:

Last time I rode it the bike ran fine, then it would be extremely difficult to start for the next moto. But run fine again once it got going.

After that it sat for a few months, but I replaced the gas before trying to start it.

Any help would be very appreciated.

Thanks!
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Paw Paw 271
Posts
3640
Joined
4/3/2013
Location
Benton, LA US
5/15/2016 5:32pm
Unless you removed the pilot jet and cleaned it completely ( all the small holes) you will not get fuel to start. There is also a starter jet that sets right by the pilot jet that also be clogged. The carb most likely needs to be removed and a complete cleaning and carb soak may be needed if fuel was allowed to dry in it over time.
Have you tried starter fluid to see if it will fire up even for a second? If it does then you know you have a fuel supply issue. If it does not then you have other issues as well.
Is your air filter clean and oiled properly?
Are you getting a good strong Bright Blue spark at the plug when you kick it over?

Paw Paw
VetTracker
Posts
76
Joined
4/1/2011
Location
Temecula, CA US
5/15/2016 5:47pm
Thanks for the help, we have taken the subframe off and sprayed some carb cleaner directly into the intake. Still won't start, we don't have a leak down tester so we will have to try and rent one from autozone or something. The pilot jet was completely removed and all holes were cleaned. I don't remember seeing another jet but we will take the carb back apart and look for the starter jet.

Since it didn't start on the carb cleaner directly into the intake, we probably have other issues.
RyanLester761
Posts
1133
Joined
2/7/2007
Location
El Dorado Hills, CA US
5/17/2016 8:29am
I would try a new spark plug. It might be shorting inside, although it appears fine. I bought two Champion plugs (in an emergency) and both wouldn't start the bike (2004 kx250 2-stroke), even though they were brand new. I finally got an NGK and it fired up.

The Shop

racinstation
Posts
807
Joined
5/18/2013
Location
Driggs, ID US
Fantasy
1912th
5/18/2016 4:43pm
What were your intake valve clearances? Also if your cam timing is off it will not start. Make sure the marks line up at top dead center and make sure the intake valves clearances are all on the money. The center intake valve on this bike is the one that gets tight so pay closest attention to it.

I have also seen a bad coil act just like this, but the plug would be wet if that was the case.
BobPA
Posts
8030
Joined
10/31/2013
Location
PA US
5/18/2016 10:35pm
I am betting it is low compression...

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