Jetting changes

[CorvetteZ06]

Hey guys, going to be adding a FMF Q4 exhaust, k&N filter w- no lid on my airbox, and a Hot cams stage 1 to my other wise stock motor/carbed 250X. How many sizes do you guys recommend going up on the main and pilot?

[rooster300ex]

Its gonna be trial and error. I would get a few different sizes bigger, maybe mess with your needle position, and turn your fuel screw out about 3 turns depending on your elevation.

[magos]

Wow, I get to help!

I put on a 38 pilot/slow and a 138 main for a setup of:

K&N w/NO airbox, stock engine, stock carb, full Cobra exhaust. If it's starving at idle and low throttle, try a 42 pilot/slow.

Hope that helps!

PS - I have my throttle at the middle clip (stock) and I'm running a 96 300ex carb (basically same thing).

[CorvetteZ06]

Hey guys, thanks for the replies! Magos- what's the
Difference in the 300EX and 250X carbs? Thank you!

[magos]

Ya know - I'm not 100% but I can tell you that the 250x and 300ex and nearly the same machine. I hear the 250x is a stroker in comparison and of course, the 300ex has a larger displacement. Most everything is interchangeable as I've learned. I'm fairly new here but I have learned a ton off this forum. Lots of guys here to help and I'm sure they will have the answer.

The reason I'm running this carb is that I tried a 400ex carb and wow did that suck. Not recommended unless you are very patient. I had it running but it was 'off' all the time. This carb is much more stable and I like the way it runs now. Granted, I'm selling it because I need to move up to a 450 to be competitive. Good luck and drop me a line if you need anything.