'03 YZ250F & WR250F Standard Jetting

James_Dean

Posted 25 October 2002 - 06:14 PM

It would help, for future reference, to know the "Standard" '03 YZ250F jetting.

The Yamaha website lists the '03 YZ250F jetting as:

Main Jet #178
Main Air Jet #200
Jet Needle 0BELP-4
Needle Jet 2.9mm (I.D.)
Pilot Air Jet 1 #100
Pilot Outlet 0.9
Pilot Jet #40

Previous model year owners can use it for comparisons and mybe help with jetting.

When the WR250F becomes available, the same information would be useful too.

Thanks,

James

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bhunt

Posted 25 October 2002 - 06:25 PM

I just got the YZ250F yesterday. I am going to ride it on Saturday. It dies if I hit the throttle from Idle. Lean condition? What do you experts think?

Posted Image

Thanks

Brian

YZ250F_Rider

Posted 26 October 2002 - 03:38 AM

Just go to yamaha. They publish the info.

YZ250F_Rider

Posted 26 October 2002 - 03:44 AM

bhunt,
You can't whack them until the carb is fully warmed up. The 03's act and feel leaner than the 02's. The needle for sure is too lean for trail riding (putt puttin).

If it still dies after a thorough warm up, check the accellerator pump.

James_Dean

Posted 26 October 2002 - 06:22 AM

Brian,

Is the jetting listed below correct?

The Yamaha website had it: www.yamaha-motor.com/products/unitspecs.asp?lid=2&lc=mcy&cid=7&mid=12 There is a nice feature to compare model specificatins side by side within the website.

The '03 YZ250F jetting is listed as:

Main Jet #178
Main Air Jet #200
Jet Needle 0BELP-4
Needle Jet 2.9mm (I.D.)
Pilot Air Jet 1 #100
Pilot Outlet 0.9
Pilot Jet #40

The pilot jet seems on the lean side, try turning the fuel screw out with a #40 pilot jet unless at higher altitude and warmer temperatures.

Thanks

James

'03 YZ250F & WR250F Standard Jetting

James_Dean

bhunt

YZ250F_Rider

YZ250F_Rider

James_Dean