There are two main air bleeds in our carbs. There are other bleeds
but the ones that give us the most problems are the Pilot Air Jets
or PAJ1 and PAJ2 . PAJ1 is located on the top of the carb (#2 in
diagram below). You have to remove the airbox or filters if you have
individual filters to get to it. If you are facing the carb when it
is mounted on the bike you will see at the 6 o'clock position a
large oval shaped hole and 4 round holes. Going counter clockwise
starting from the oval hole the PAJ1 is the second round hole. It is
the one that has the largest brass jet in it. The next hole or the
third one in line has a smaller brass jet in it and it is the Main
Jet air bleed. The PAJ2 is located behind the slide diaphragm (#5 in
diagram below). You have to pull the cover off the side of the carb
and pull out the slide to see it. It is the hole with the brass jet
screwed in it. It is located at about the 3:00 position next to the
oval shaped hole in the top of the housing which is connected to the
oval shaped hole in the top of the carb. The PAJ1 and the PAJ2 are
connected to the idle circuits of the carb. Whenever any dirt gets
into the air bleed circuits it causes a rich mixture. What we
experience is the bike runs like it has an intermittent bad spark
plug in it. The blocking of the air jets can cause other problems if
it is sever enough but this is the most common complaint.
What I do to correct the problem is:
Pull the air box off.
Pull the slide out.
Remove the idle mixture screw.
Shoot a little carb cleaner in the air bleeds and blow air through
the PAJ1, PAJ2, and the hole where the idle mixture screw was . Do
this several times . You will get gas shooting out of the carb so
be careful with the eyes and no open flames.
When reassembling clean the slides and their holes with some WD40.
After installing each slide take your finger and reach in through
the top of the carb and push it back and let it go to see if it is
OK and not in a bind and they all react the same. You can actually
if you wish blow a little air in the large oval hole on top of the
carb and watch the slide action.
Install the idle mixture screws and set them at 2.5 turns out and
start the bike and then tune the carbs.
actually do this procedure at every other oil change and I also
replace the spark plugs. This keeps a crisp running bike.