CRF's Only Forums

Hi Everyone - My '05 CRF250R idles rough and I cant figure it out for the life of me. I noticed a few weeks ago while riding that it was idling a little rough and popping on decel. Since then, I have done the following and it still idles rough (haven't ridden it around much so unsure if it still backfires):

- Cleaned and Rebuilt the carburetor (Bought the All Balls 26-1006 Carburetor Rebuild Kit)
- Re-jetted the carburetor (Purchased a JD Jet Kit & followed the instructions: 175 Main Jet/Red Needle in 4th Position)
- Installed a new spark plug (NGK (7791) R0409B-8 Racing Spark Plug)
- Installed a Yoshimura RS2 Full Exhaust (Replaced the crush washer between cylinder head and exhaust header pipe)
- Unscrewed the Fuel Adjustment Screw 1-3/4 turns
- Played around with the Idle Adjustment

My plans are to replace the Fuel Filter, play around more with the Fuel Adjustment screw, and spray carb cleaner on and around the carb to see if there are any air leaks.

Does anyone have any other ideas? This was my first ever carb rebuild, but I tried to just take my time and be very meticulous about everything so I'm fairly confident it was done right. I'm still fairly new to working on bikes so any help/advice would be much appreciated.

Thanks!

Do you have the workshop manual and have you checked the valve clearance.
How old is the fuel? Is it premium no ethanol fuel?

Just take out some of the possible causes.