250r big bore questions

[cody7781]

Im getting ready to drop a 310 big bore in my 250r. Any recommendations on which carb jets and fuels to use?

[09RappySE]

I am running a 170 main, 50 pilot and needle 3 from top on a 50/50 mix 110/93 at 40:1.

[350for350]

Ask your parts supplier. They can at least get you in the ballpark on jetting. Jetting can be very finicky at times. Don't expect to put it together and have everything perfect. Not a trike, but on my Tecate 4 with a 330 kit, my engine builder suggested a 340 or 350 main jet and I have a 430 in it right now. I still haven't quite nailed down the pilot and I know that I should get a different needle too. I just haven't been riding it much since a guy ran it into a tree. In fact, it hasn't left the garage since last November.