Aug 11, 2002
I have a friend who bought a brand new 2006 WR250F last year and has had problems from the start. From what he says, it runs like crap. The dealer has not been helpful.

Are there any known issues with this year and model? He thinks maybe an accelerator pump problem? Hesitates and bogs when accelerating.


Old MX Racer
Oct 19, 2006
Check the plug off bottom for reference. FCR carb,ap adjustment,leak jet,pilot,clip and main! Checking the plug is the hard part. JD's working miracles,or learn to jet yourself! On the hondas' the leak jet is putting too much fuel in and causing a bog,at night with the bike idling the header pipe glows! It is burning fuel in the pipe! Turn the choke on and it gets worse! A larger numbered leak jet took care of the problem. The ap adjuster floats,allot! The o-ring helps it pump every time! Wire it solid works also,but bottoms out the ap rod in the diaphragm. I have reservations about the nipple mod,as I believe it changes the volume of the pump.


Jan 27, 2000
Jackpiner57 said:
Are there any known issues with this year and model? He thinks maybe an accelerator pump problem? Hesitates and bogs when accelerating.

There are a few things to check.

Make sure the carb is clean and there is no sediment in the accelerator pump area. Adjust the pump rod so that the slide opens a little bit BEFORE the AP rod starts to move. Many of the systems in your carb do not work until the slide opens. Some people adjust the AP to pump more gas, sooner. Thinking more is better. This is not always true. If you inject too much gas into carb before the slide opens it will flood the engine and cause a bog.

Also, make sure the hot start valve is in good condition and closing all of the way. Remove the hot start valve and inspect the rubber on the end. There should be a ring shaped indentation on the rubber pad where it seats on the orifice. If the rubber is damaged or the ring shaped indentation is not there, the hot start valve is not closing all of the way.

There are also a few free mods that you can make on the WR's. There is a connector under the gas tank about mid way down the frame tube that has a grey and black wire on it. Cut the grey wire and tape it off. This will make a noticeable difference in the way the bike runs.

Remove the deflector on top of the air box. This lets more air into the air box.

Check the carb for full throttle. Remove the air box and look in the back of the carb. If the carb is not getting full throttle, cut the throttle stop screw until it does.

Re-route the breather hose that comes from the top of the engine and goes down the front frame tube. Re-route it so that it goes back to the air box and dumps into the air box. If this hose becomes partially clogged with mud or dirt it will affect the way the bike runs. If it becomes completely clogged or gets under water, the bike won't run at all.

Hope this helps. :cool:
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