I got a 1992 lt250r it has vforce 3 reeds with an fmf fatty system and the stock air box. I'm at sea level it's about 0 degrees celcius outside most days in winter, I just bought the quad but the problem I'm having is between zero to roughly half throttle the quad just sputters but it dosent fall on it's face and after about half throttle it starts to clear up! The problem is mostly occurring in the lower gears! It's currently got a 30 pilot and 260 main which is what fmf recommends, but the quad came with a 50 pilot and 280 main  and it was worse with those! The plug runs a dry sooty grey/black but never fouls. I was wondering if you guys could give me a few ideas on a rough jetting spec. Thanks a lot!!

If it doesn't want to idle when the slides adjusted properly you should drop the pilot jet a size till it idles right, then see how its runs in the mid

Need to take needle out and jet needle, brass piece needle sits down and post what size they are.