[keithb]

I bought an 06 crf250x and it is totaly stock, any suggestions on the cheapest and easiest mods I can do that will help me get a little more response?

[Asmith]

Open up the AirBox, Change filter to Twin Air Power Flow(flame resistant), Remove backfire screen, Rejet with JD Jetting Kit, Replace pilot jet with # 42, Do AP mod with O-Ring, Replace fuel screw with CRF'sOnly fuel screw, Modify exhaust baffle by cutting off one disc and drilling 1/2" hole in remaining disc.

It'll feel like a new bike.

[keithb]

What is the AP mod with O-Ring?

[Asmith]

What is the AP mod with O-Ring?

The JD jetting kit will come with two O-Rings. They are used to modify the Accelerator Pump on the carb by eliminating lag time between the throw arms. Eliminates the off idle bog that some experience when snapping the throttle quickly.

[JimmyPwadd]

When it comes to spending my hard earned $$$, I am a tightwad. The very first thing I did was remove the snorkel and open the top of the air box. http://www.rickramsey.net/CRF250Xmymods.htm#airbox
The second thing I did was cut the plugs off of the baffle inside the spark arrestor to get my X breathing better. http://www.rickramsey.net/CRF250Xmymods.htm#diffuser I then pulled the pink wire (behind the battery on the left hand side) http://www.rickramsey.net/CRF250Xlg/PinkWire1.jpg from its stock location and reinserted it in the "blank" position below it in the harness. I don't if this mod did much but every bit helps! http://www.rickramsey.net/CRF250Xlg/TheWrench.jpg
Then I opened the air/fuel srew mix up a bit., getting your bike breathing better leans out you air fuel mix. ( I highly reccomend aCRFs Only mix screw!) All of this was FREE!
I then went to spending so money. Some people just re-jet and drop the clip on the needle down one position which would be the cheaper way to go. BUT I think the JD kit was $70 well spent. When I bought my 250X I was rather disappointed with the ooompf, the bog and the holeshot. At the same time I installed a Boyesen Quick Shot and tethered the AP linkage together. (since I had the carb in my hot little hands) These made my X a TOTALLY different machine for around $130.
That's my story...........so far!

[PhilM]

Did opening the exhaust baffle make it louder?? If so, by how much.

Thanks

[crf~rob]

Has anyone tried the little 1" circular filtered air vents? I believe they come in a pack of six.

Are they any good? How much air do they produce? I was curious if this is a alternative to cutting the top of the airbox up?

thx

[keithb]

ok, I installed the jd jet kit. 158 main, red needle in the 5th position, ap mod with the heavy o ring, opened the airbox and drilled a 1/2 inch hole in the diffuser. I bought a #42 pilot jet from a local dealer and it was for the wrong carb. How important is changing this pilot jet? (I am not looking forward to ever going into this carb again, wow what tight fit) is this richer or leaner than stock? also I have left the stock filter on, can I use the stock filter and still cut out the backfire screen?

[Asmith]

ok, I installed the jd jet kit. 158 main, red needle in the 5th position, ap mod with the heavy o ring, opened the airbox and drilled a 1/2 inch hole in the diffuser. I bought a #42 pilot jet from a local dealer and it was for the wrong carb. How important is changing this pilot jet? (I am not looking forward to ever going into this carb again, wow what tight fit) is this richer or leaner than stock? also I have left the stock filter on, can I use the stock filter and still cut out the backfire screen?

The pilot on the 250X is important. The bike will have some off idle bog that will be hard to correct with the stock 40 in there. The 42 makes it slight richer than stock. Easy to start, no bog, warms up faster, but runs cooler.

The stock filter shouldn't be used without the backfire screen. Switch to a twin Air flame retardant filter when you can and remove the backfire screen. BTW this will make the least amount of difference in all that you've done, but every little bit helps.

[keithb]

stock is 40? I could have sworn it had a "55" printed on it. was I looking at the wrong jet?

[Asmith]

The "55" is most likely the leak jet. Is it next to the main jet "up" in the carb? Or is it in the bottom of the float bowl?

[keithb]

in the bottom of the float bowl.

[Asmith]

in the bottom of the float bowl.

That is the leak jet. The 55 is fine.

The pilot you have is most likely the correct one. The pilot is directly forward of the Main jet. You would use a thin, flat blade screwdriver to remove.

The fuelscrew ties into the pilot jet circuit, and controls it. The fuelscrew is on the front of the carb bottom.

[keithb]

can you get to the the pilot jet through the main jet access or do you have to temove the bowl?
(thank you for all of your help!)

[Asmith]

can you get to the the pilot jet through the main jet access or do you have to temove the bowl?
(thank you for all of your help!)

You can get it from the 17mm plug on the bottom.
(remember Japanese hands are much smaller)

It is slightly recessed, use a thin screwdriver so you don't break the casting.