fcr jetting

[polinipower]

hello i have an 2002 426 ex with the following mods 426piston 11.1 ported and polished head oversized valves and springs webcam and a sparks x6 pipe with an 39mm fcr carb with open aluminum air box and i cant get it jetted ive got now 195 main 45 pilot. it just stutters when i got 31/4 trothle does anyone have kinda the same mods and could maybe lead me to an way to get it not to stutter thank you.

[d3ktrix]

The sputtering is a sign of a rich main jet.

Keep dropping main jet sizes until it goes away.

190MJ for an FCR is huge.
Even for a ported big bore 450.

[supraloud84]

I have the fcr on my 440 and when I went to a 190 main jet for cold weather riding and it fell on its face just likee you described. It is way to fat. I went back down to a 170 for the mid range temps (50-70 degrees F) and my machine runs like a raped ape now. I would lean it out quite a bit if I were you. maybe start with a 175 main and see how that goes and just step it down from that to dial it in.

[rt20ps]

That 45 pilot is too rich too. I would try a 40 or 42.

[downeyballz]

the needle makes a huge diffrence in fcr carbs. they make alot of diffrent ones