Okay so a little back story first, So I bought an 05 KFX400 for $800 with a cracked case. Found a used case on eBay and went ahead and began installing it. Well I realized while installing the piston that I had an over-sized piston. Took some measurements and discovered it had a 434 bbk installed on the bike prior to me purchasing it. I thought to myself “well that’s a plus”. Finished the install went to crank it and nothing. Decided to buy a ignition coil and a new carb. Installed them once they arrived and it fired right up, literally instantly. Well drove it around a bit and realized it would bog down on 1/2 throttle and beyond. If I ease into it it’ll accelerate just fine. So i started playing with the jetting. Now the carb I bought on Amazon has a 130 or 135 main jet and a 22.5 pilot jet When I received it. Not sure the needle clip position. Well I removed the fuel screw plug and started adding different sized main jets. Went to a 140 with the screw 2 and 1/2 turns out. Still rich based on checking the spark plug. Tried the 130 jet and moved the clip to the leanest position possible. Still rich. Ordered some main jets online. Put in a 120 jet. Still rich. I’m at a loss. I have no idea why I’m still running rich. I’ve got the air box lid off, from what I can tell stock exhaust and the rest is stock minus the bbk. The weird thing about it is if I put the fuel screw all the way in, and I mean ALL the way in it shows some improvement but not much. Right now it has a 100 jet in it. Yes that’s right a 100 main jet in it and it’s still running rich. I’ve tried every combination possible with no real improvement. The bike has very little power and I’m about to give up. The valves have been checked and adjusted to spec and all other work that was done was done per service manual instructions. Any and all help would be greatly appreciated.