250sxf sputtering during exceleration

Ok, a little history. Bike leaked gas when I purchased it. Go a carb kit and it was fixed immediately. I checked the valves today and they were spot on. Rode it around and it seems to have some good sputtering while I'm on the gas. Played around with the air/fuel screw and it didn't seem to help any. Thoughts/suggestions? I haven been able to find a tool to get the spark plug out yet but it looks like ill have to buy one. Could this be a bad plug? Bike starts good, sometimes when it's heated up I have to use the hot start a few times and it always does the trick.

Any help would be appreciated!

Update: finally pulled the plug and its definitely rich. Nice and black so I cleaned it up. How much smaller would you recommend on the main jet?

are you sure its the main that's rich? could it be the needle or pilot ?maybe you just need to set your float.

It had been leaking fuel before but im pretty sure it was the needle that is connected to the float that was bad. I replaced that and it worked fine. I checked the float height and it seems to be perfect. Probably have to play with it and see what happens.

It depends on throttle position.

Sputtering alwasys means rich (or an ignition problem)

Anything below 1/2 throttle is the needle, above is the main

The needle is in the stock position. Ill try going a tad smaller on the main and see what she does. I would definitely say its on the upper end where it cuts out and sputters.

I just pulled the main jet and it was a 185....way to big for stock. Below are my settings.

Main 170

Idling 42

Main Air 200

Idling air 100

Needle at 5th position

Air/fuel mix at 1.5 turns out

I cleaned the plug really good and rode it for about 15 mins. Bike definitely feels good and no sputtering or anything. Plug is slightly dark (black not grey) but definitely not soaking like before. If the bike acts fine is slight blackness ok or do you think I need to go lower on te main? Valves are 100% perfect as well. No issues starting or stalling.

Thanks...been way to long since I've touched a carb.

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