Hello! Very experienced mechanic here! Bike runs amazing, but isn’t jetted correctly! I was given a 2009 KLX250sf by a old friend. He had a full HMF exhaust installed years back. Rode it for 2583 miles, laid it down lightly(small scratches no damage) then let it sit for 6 years. I got it and sonic cleaned the carb, jets and all! I noticed the main jet was a 120! The stock jet for research was a 118. So it was upjetted a little! HOWEVER!!! Here’s the weird part, when I’d go to start it, it starts just fine but won’t rev past 6K rpm, sounded like a rev limiter almost. With some work, I found it was WAYYYYY to lean! Temp gun on the exhaust and hand over the carb intake allowed it to rev fully out! So, I did some experimentation with the air box and found if I taped exactally half the snorkel off the box it runs AMAZING! I’ve had it on 70+ mile rides, 80mph…. But I feel like I’m half assing it, it shouldn’t require half the snorkel taped off…. I’m wondering if it’s a jetting issue? With a full aftermarket exhaust what type of jets are you running? Any ideas or thoughts would be cool! It’s a strong, quick bike but I feel like it could have some hidden power I haven’t unlocked yet 😂 any tips or tricks would be awesome!! Thanks