This is to anyone that can help! I have an '03 crf450r that I'm having some problems with the idle on it. It either idles too low and stalls or of course I can turn it up all the way to the point of I may as well hold it at quarter throttle. There is no in between. It's bone stock except for a R4 silencer and I replaced the clutch. All the jetting is stock. It ran great until about memorial day and that was it. It's real hard starting, too. I checked valve clearances and they seem to be fine. They're a little tight but I'm within the + or - range.
Any advice is greatly appreciated! Thanks, Bruce