250F 2001 WR250F problems

MY-BLUE-BEAST

MY-BLUE-BEAST

I am working on a friends 2001 WR250F getting it running and such. I got the bike to start and it starts on the first kick, idles great, and the low end is awesome. Then there is the dreaded BOG when I go to snap the throttle. I know I can figure it out if I had the time to work on it, but I am leaving town tonight for the weekend (good thing he is gone for the weekend to so no rush :smirk:) and would like to here suggestions on what's what. Here is the set up:

Main 175
Pilot 50
Needle 3rd from top
Leak 40
throttle cable has a perfect snap to it
TPS is unplugged (I tried it plugged in)
Air Cut Off Valve Jet is 100
All free mods
Grey Wire is unplugged (tried that plugged in to)
New Gas 91 Octane
New spark Plug (according to him, maybe I should check)
And he had the valves adjusted at a shop about a year ago

Not sure what is going on with it, its all clean and starts easy just doesn't want to ride and almost dies when the throttle snaps. Am I missing something? Is there a trick to these older WRs?

Ill figure it out eventually but I would love to here what you think.

Thanks :thumb:
 
timoyz

timoyz

Pull off the sub frame/air box, and look into the back of the carb when you snap the throttle. You will be able to see the accelerator pump squirt when you do, make sure it clears the slide, and goes into the intake. I had this problem with my Sons 01, and had to fiddle with the AP timing. Other then that, make sure that carb is clean, and when it is clean, clean it again.:smirk:
 
MY-BLUE-BEAST

MY-BLUE-BEAST

timoyz:
Pull off the sub frame/air box, and look into the back of the carb when you snap the throttle. You will be able to see the accelerator pump squirt when you do, make sure it clears the slide, and goes into the intake. I had this problem with my Sons 01, and had to fiddle with the AP timing. Other then that, make sure that carb is clean, and when it is clean, clean it again.:smirk:
Click to expand...

I knew I was forgetting something, I have heard about the AP timing just have never really done it before so I didn't even think about it. How do I go about adjusting it? I will definitely pull the carb and clean it again.

Thanks
 
SRAD97750

SRAD97750

Moderator
Staff member
Accelerator pump timing, or
I am thinking the leak jet is too big if you are getting a bog when snapping the throttle. The DRZ guys plug their leak jets completely to elimininate the accelerator pump bog. Not sure if this will help you, but a smaller leak jet allows the accelerator pump to pump more fuel and let less fuel bypass the pump. -BIG DAN:thumb:
 
MY-BLUE-BEAST

MY-BLUE-BEAST

SRAD97750:
Accelerator pump timing, or
I am thinking the leak jet is too big if you are getting a bog when snapping the throttle. The DRZ guys plug their leak jets completely to elimininate the accelerator pump bog. Not sure if this will help you, but a smaller leak jet allows the accelerator pump to pump more fuel and let less fuel bypass the pump. -BIG DAN:thumb:
Click to expand...

The leak jet is a 40 the same size in my 450, should I go smaller? it looks like 35 is the smallest. How do I adjust the accelerator pump correctly? There is a screw on the throttle side behind the cover should I mess with that? I will have to play with it when I get back.
 
MY-BLUE-BEAST

MY-BLUE-BEAST

josmoloco:
lets see some recent pics of your WR450 :devil:
Click to expand...

temporary_zps1796fbad.jpg


Here is the latest I have. That's my WR furthest away, and my brothers WR is the closest one.
 
MY-BLUE-BEAST

MY-BLUE-BEAST

Well the AP diaphragm is completely destroyed. Im not sure how it happens but it is all torn up and good for nothing. I would put a picture up, but in my pissed off rage I threw it away haha. I gotta order a new one and then the 250 will be back to normal.

Thanks for all your help
 
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