I Thought This WR250F Was Running Lean... I Was Wrong

Still chasing a bog? Download my FREE 4-Stroke Fuel Screw Tuning Guide and learn how to quickly tell if your pilot circuit is rich or lean. https://motocrosshideout.com/fuel/ A customer brought me this 2008 Yamaha WR250F because it still bogged badly... even after the carburetor had already been rebuilt. At first, I was convinced it was running lean. After testing, changing parts, and chasing multiple possibilities, I realized the real problem was something completely different. In this video I'll show you the entire troubleshooting process—from the wrong turns to the final fix—so you can avoid wasting hours (and money) diagnosing the wrong problem on your own dirt bike. Whether your WR250F bogs, hesitates, falls flat on acceleration, or just doesn't run right, you'll see the exact steps I use to narrow down the cause instead of just replacing parts. Parts/Tools Used: -Borescope - https://amzn.to/4ff7L1O (Amazon) -FCR Carb tool - https://amzn.to/4au9Fch (Amazon) -JD Jetting kit - https://motosport.sjv.io/xJOaxA (MotoSport) -FMF powercore Slip-on muffler - https://motosport.sjv.io/m4Nq6e (MotoSport) -Scissor lift stand - https://amzn.to/4yiVi51 (Amazon) Chapters: 00:00 WR250F Symptoms & First Start 01:23 First Test After Carb Rebuild 03:33 The Hot Start Theory 08:53 Needle Adjustment Goes Wrong 11:33 Accelerator Pump O-Ring Mod 15:01 The Real Problem (Not the Jets) 17:42 Final Test Ride 18:57 Final Carb Settings & Results 📍 Need your dirt bike carb diagnosed or tuned? I offer carb tuning and diagnosis through Fager Powersports in Oak Grove, Minnesota. Serving riders around Andover, Blaine, Coon Rapids, Elk River and the north Twin Cities. https://motocrosshideout.com/fager-po... 🛠️ More beginner-friendly dirt bike help: https://motocrosshideout.com/ 📍 Minnesota beginner dirt bike coaching: https://motocrosshideout.com/dirt-bik... 🎥 Carb tuning courses & riding guides: https://motocrosshideout.com/courses/ 👕 MXHideout merch: https://mxhideout.printful.me/ Some links may be affiliate links, which help support the channel at no extra cost to you. Ride safe. Have fun.