CRF100 Carb ('04) So many variables

I added an FMF pipe to my son's CF100 and did a 38/102 jet combo.  I pulled the needle up one notch, and drilled (3) 3/4" holes in the top of the air box.  Cranked up first kick, no choke, ran seemingly fine.  We went to the trail Saturday and did a lot of riding.  It seems after the bike got fully warmed up, It would hesitate for a moment under load through slight throttle input before running smoothly.  I looked at the plug afterwards and it seems to be running rich.  I took off the air box cover and took it for a spin and it ran a lot better without hesitation.  I'm considering dropping the needle back down a notch as opposed to going with an "open" air filter.  I've also read where others have left the pilot jet alone and stuck with the stock 35.  


Any input based off of my scenario?  


We were riding at 700" and the temp was around 88.


Thanks, KR

Dropping the needle sounds like your best bet as opposed to removing the cover and letting all of the dirt and water get in.


I owned a crf100f about 5 years ago but cannont remember the jetting for the life of me. I had the bbr 120 kit, k&n air filter, bbr revbox and those airbox vents.

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