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Hi all. I bought a used 2006 250x a few months ago and it came with a Powerbomb header and an FMF Q2 pipe. It was rejetted as:

Main: 152
Pilot: 42
Leak: 70
Needle: NCYS (different than stock NCVT)
Clip: 4th position
Pilot Screw: 2 1/4 turns out

It also has a quickshot 2 installed and the bike seems to run pretty good (no bog, good acceleration, etc.). However, I don't really have anything to compare it to and wonder if I can get more out of it by rejetting based upon what I've read on this sight. I thought about just installing a JD jet kit but I don't want to go through the time/cost if it won't improve much over what I have now. What do you think?
Thanks!
Scott

P.S. I've also cut out the airbox and removed the backfire screen.

Hi all. Any ideas on whether I should rejet?

Alot depends on your elevation and everyones bike is slightly different,, but these are my suggestions to try or maybe just compare to my trial and error.

I personnally don't like the #70 leak jet , use a #55 which I believe is stock. With a smaller leak you'll get more fuel out of your accelerator pump for better response.

If the exhaust and intake are really uncorked , not just slightly, you may find you want to go up on your jetting.

My 04 / 250X with stk header and FMF rear slip-on, Pink wire mod , stk cam is running these settings.

Slow jet - 45
Main jet - 155
Leak jet - 55
Needle clip - 3rd down
fuel/air screw - 2 turns out

I run 93 octane pump fuel,,,,, we'll talk additives another time as I'm in the Industrial chemical business.

Elevation - 700' ft above sea level.

No bog , No cough "girgle" , runs very strong !

YES , the air box has been modified also.

Thanks - I'm at about 200-300 ft. I'm not sure why they replaced the leak jet and made it so large. I've got the stock leak jet that I can reinstall. Do you think installing the JD jet kit with the red needle would be helpful?

In the Honda Closed Course Competition settings chart that Honda published , it showed installing the #70 leak Jet. Alot were replaced without realy knowing what it did and some assumed the bigger the better.

Most have found the stock #55 works the best.
Even the 2008 CRF250R works far better with a 55 than the 70 thats stock.

I'm amazed at the people running a 160-165 main jet,,,,, I havn't tryed it so I have no comment besides if you ride at 10,000 plus rpm's most of the time , then I can see where it would work good.