|
Introduction:
At this point, you should have
removed the airbox, the old carburetor, the manifold, the reed
cage, and the old throttle cable. It is also a good idea to
de-restrict the stock reed cage (see step 3
and picture 1). Do not install the
new throttle cable on the carburetor at this time. The carburetor
should be disassembled to the stage as seen in
picture 6. The slide needs to be
out of the carburetor body. There is a specific order that the
carburetor install must proceed. If your manifold (Mikuni 24mm
kit with 19mm manifold) has a mysterious hole in it, this is where
the oil injection spigot goes. The old oil injection spigot
must be removed from the old 12mm carburetor. It is just
press-fit in. Use some gasket sealant on it and install it in
the 19mm manifold. Lightly tap into place with a metal hammer.
If you plan to run pre-mix only oiling, then you must come up with a
way to block-off the oil injection spigot. It cannot leak air.
Also remember, carburetor settings differ greatly between oil
injection and pre-mix.
Installing the reed cage and manifold:
Re-install the reed cage, and
bolt on the new manifold (see picture 2).
Be sure to install the ground wires to the top left bolt, and the
clutch cable holder to the lower right side bolt.
Throttle Cable Installation:
To install the new throttle
cable, first the oil pump must be disconnected (see
step 3 and picture 3). Then the
cable splitter can be pulled apart. Install the new throttle cable
into the splitter (see picture 4).
Loop the cable ends into their respective slots inside the junction
block (see picture 5). Close the
cable splitter. You can now re-install the oil pump cable (see
picture 13) back onto the oil pump. To continue installing the carburetor, first
the carburetor top must be installed on the cable (see
picture 7). Use all the supplied rubber boots, as this can be a
source of an intake air leak.
Throttle
Cable to Carburetor Slide Installation:
With the e-clip installed onto
the needle, install the needle into the middle hole in the
carburetor slide (see picture 8).
Next install the carburetor slide spring over the throttle cable.
Pull the cable end through the middle. With your hand or
carefully with a pair of pliers, hold the spring compressed and grab
the free cable end. Next, install the white needle hold down part
(spring perch) over the free cable end. Put the free cable end
into the slot in the slide body (see slot
in picture 8). Slowly release the spring tension.
Make sure the plastic part is fully seated. The finished
result will look like picture 9.
The order of the parts threaded onto the throttle cable are the
carburetor top, gasket (small o-ring on Dell-Orto 21mm and a paper
gasket on a Mikuni 24mm), slide spring, spring perch, and finally
the slide.
Finishing
Up:
Carefully install the slide into
the carburetor body. It can only go in one direction. Be
careful with the needle. It needs to be inserted into the
emulsion tube (see picture 10).
Do not force the slide down. Install the two carburetor top screws.
Now is a good time to test the throttle action at the grip. Ensure that the
slide goes up and down smoothly and fully. It should move very
smoothly and return on its own. If not, check cable routing,
and for other sources on binding. This can be very dangerous,
if not fixed. It could lead to a stuck wide open throttle.
Install the carburetor to the manifold insuring an airtight seal.
Attach the oil injection line (cap off injection spigot for pre-mix
running engines). Notice where the fuel line attaches (see
picture 11). Finally install the inlet adaptor, and either
the airbox or pod air filter. Note, carburetor settings differ
greatly when running the stock airbox versus a pod-style (clamp-on) air
filter. The 21mm Dell-Orto kit comes pre-jetted for the stock
airbox and oil injection. Using a pod filter will require
significantly richer jetting. Running pre-mix will also
require richer jetting.
Adjustments:
Note the positions of the air/
fuel mixture screw and idle speed adjustment on the Dell-Orto 21mm
as shown (see picture 12).
Also, note the vent line which must simply be vented to the
atmosphere (see picture 12).
Note on other types of carburetors there maybe more than one vent
line. The Mikuni 24mm carburetor idle speed adjuster and idle
air/ fuel screw adjusters look very similar.
To lower your idle
speed, rotate the adjuster counter-clockwise (loosen). To
raise your idle speed, rotate the adjuster, clockwise (tighten).
A couple of small turns is all that is every really needed.
To richen the idle
and low speed mixture, rotate the adjuster counter-clockwise out
with 1/4 turn increments. To lean out the mixture, rotate the
adjuster clockwise in 1/4 turn at a time.
Note that the idle
mixture screw does NOT affect any RPM greater than just off-idle.
It will not cure a lean or rich wide-open or part-throttle running
condition. This adjustment is made with mainly with main jets,
needle clip position, and to a lesser extent the pilot (slow) jet.
Tuning and Final
setup is the next chapter.......
|
