1998 CBR F3. around 15,000 miles. Bone stock except for air filter.
Recently completed a carb clean and rebuild due to slow speed jets
being clogged. Slow speed jets were completely removed, blew them out,
theyre definitely clean. I also sync'd the carbs. The pilot screws were
adjusted to the suggested factory manual's setting of 1.5 out (as a
start point). After the carb sync (with the airbox/filter removed) youd
quickly give the throttle a blip and RPMs would rise quickly.
I then put the airbox/filter back on to adjust the Pilot screws. Of
course, the motor was at operating temp. I immediately noticed the bike
was running rich with the airbox on. I couldnt get much of a change in
RPMs at all turning the pilot screws. I also noticed youd give the
throttle a quick turn and it would fall on its face, too much too soon
and it would stall. No, the choke isnt on. Maybe I dont have the ear to
adjust the pilot screws, and I just cant tell of a slight idle drop by
looking at the factory tach.
If I turn the throttle slowly until about the 2000rpm mark, then open it quick,
its fine. Its only that quick fast turn of the throttle off idle where
the hesitation is. Even though the idle is a bit lumpy, it still idles good and starts great.
I pulled the #1 plug, looks great.
The filter is a KN.. but has about 1000 miles on it.. its no where near dirty, and no where near soaked in oil..
No modifications on the bike at all (except for that air filter).
Suggestions?
The pilot screw.. Im assuming on this bike it adjusts fuel delivery? Screwing it in makes the mixture leaner?
Im also buying the Fluke rpm80 inductive probe to hook to my Fluke DMM
to get a better idea of that very small slight drop in idle when
turning those pilot screws.