I bought my 2003 Honda CR250R with a Factory FMF Fatty, FMF Shorty, Twin-Air Air Filter, and a ScaryNow Powernow already installed. There wasn't any change with the jets... I figured that changing the jets would help with the aftermarket parts, so I went to FMFracing.com and looked up their recommended jet setup for the bike.
Stock Main Jet: 440
FMF's Main Jet: 400
Stock Pilot Jet: 30
FMF's Pilot Jet: 40
Stock Needle & Clip Position: 38-73 2nd clip pos.
FMF's Needle & Clip Position: 38-70 1st clip pos.
After putting the FMF/Dirt Rider magazine recommended jet setup in, the bike ran extremely rich. I'm running 40:1 fuel in it. If any of you have tips or suggestions on what I should try next... i'd appreciate it.