Off idle flat spot

[bournie]

My big bike (2004 yz250f) has a slight flat spot of idle
Is this normal(I just had the whole thing fully rebuilt and they said they checked the jetting and igniton 2700.00)
It has a kiehlin fcr carb (they have a AP)

 

[sean01]

flat spot can be a number of things, but id be checking the acc pump timing.
you may want to do the o-ring mod to the carb..

my 450 had a mad off idle bog to the point where you'd nearly axe yourself every time you were hitting jumps where you needed to crack the throttle a little..

i done this mod and it pretty much fixed it..

google it or youtube it

 

[themountain]

:dito:
Look on Thumper talk for " O-RING MOD"...on early FCRs the acceleration system must be adjusted...the pin in the membrane is often to grind down or you get away with the mod above mentioned :thumbup: