[AT]

I have a JD jetting kit and an FMF Ti Powercore pipe to install onto my bike (05 CRF250x). I live in the California Bay Area at about 1800 elevation. What jets do I use? I've looked on the FMF & JD websites but can't find anything.

[Ray]

With the stock exhaust you should be at a 158 main and red need clip in 5th position. If you have not done any other mods I would say go 160 (maybe 162) with main jet for the new exhaust. Also change your pilot jet from 40 to 42.

If you really want to wake up your bike put in a HotCam Stage 1 cam, remove the backfire screen, and a 165 main jet.

[Halen]

The upgrade jetting for a bike with a FMF Ti should be: 42 main, 162 pilot, and a Red#5. I just did this exact same mod with a little help from JD (phone them with your questions)
later... Van