ss - carb pilot screw plug removal and adjustment procedure
Posted: Sun Sep 08, 2002 9:04 pm
Posted this on the Super Sherpa list, but thought this may also prove
useful here.
CAUTION: Just be sure that you are dealing with the pilot screw
cover seal whether it's brass (as on the 2002 Shepra) or aluminum.
I followed some advice posted in this group's list on how to get
access to and drill out the pilot adjustment screw BRASS cover.
Here is a summary of the detailed steps taken to gain access to the
pilot screw plug and adjust the pilot screw on a 2002 Super Sherpa:
First, know where the pilot screw sealed cap is located. It is a
BRASS round plug on the carb bottom towards the front of the bike.
Next, know that to enrichen the pilot adjustment is to turn the screw
OUT (counter - clockwise)
Then begin the task:
1. Remove the left and right plastic side panels.
2. Remove the two side screws which fasten the seat and slide the
seat off to the rear.
3. Remove the fuel tank two hold down screws at the top rear
(exposed by removing the seat.)
4. Dissconnect the fuel tank vapor vent line from top rear fuel tank.
5. Dissconnect the fuel shut off valve small vacuum valve line and
the carb inlet fuel line from petcock outlet.
Caution: Be sure the PETCOCK fuel valce is NOT set on PRIME, but
should be set in normal run so fuel doesn't run out of petcock once
carb fuel line is disconnected.
6. Remove the fuel tank by sliding upwards and back. (Two large
rubber grommets mounted on the frame interlock into grooves in the
fuel tank inside panels.)
7. Now loosen the rubber carbruetor inlet clamps at both the engine
and air box sides.
You must also disconnect a rubber vent hose from the carb top side on
the righthand (exhaust side) of the carb. I also moved the flexible
rubber idle speed adjustor knob out of the clamp to provide slack for
this to move when rotating the carb in its clamps.
8. Then Rotate the carbruetor to gain access to the bottom of the
carb float bowl in order to drill out the BRASS plug covering the
pilot jet screw.
In order to twist the carb, you must slide the throttle and choke
cables backward to the carb by moving the cables under the large
black nylon wire wrap tie clamping the cables to the frame backbone.
I twisted my carb counter clockwise when standing at the rear of the
bike and looking to the front of the bike. In other words, the
bottom of the carb was tilted out towards the exhaust pipe or right
side of the bike.
9. After rotating the carb about 65 to 85 degrees, you can have
sufficient clearance to use a small drill bit to drill out the small
BRASS plug covering the pilot jet adjustment screw. This brass plug
has a very small hole (orifice)I guess let's air into the pilot screw.
10. I used a portable electric variable speed drill and a 1/16 to
5/64 drill bit to enlarge the tiny hole in this BRASS plug to take a
drywall screw.
I only drilled deep enough to just penetrate the 1/8" thick brass
plug.
11. Next turned a drywall screw very slightly into the brass plug
and used pliers to pry out the brass plug exposing the pilot
adjustment screw.
12. At this point I recommend you count the turns out the pilot
adjustment screw is set from the factory by screwing it in until it
lightly seats, counting and documenting the turns it takes.
13. Turn the pilot screw out from closed three full turns (at least
that worked excellent for my 2002 Sherpa at sea level.)
14. Now you must reassemble in reverse order:
the carb clamps, put the throttle and choke cables back to where they
were in the clamps to the frame. Refasten the carb airbox and engine
inlet duct clamps,
(Reposition cables in clamps on the frame as necessary to get carb to
rotate back to horizontal original mounting position.)
replace the idle speed flex line in its clamp, reinstall the fuel
tank,
reconnect the fuel tank vent hose, reconnect fuel petcock vacuum
line, and carb fuel inlet line to the fuel petcock. Fasten the fuel
tank mounting bolts (use blue loctite (TM)).
BE SURE TO CHECK throttle and choke cables for free and unbinding
operation throughout the range of steeing movement.
15. Leave the plastic side panels off for the time being, but re-
install the seat sliding it forward to interlock into the tang on the
frame and tank top.
Use blue Locktite on the two side seat bolts.
16. Next, check all over to be sure you haven't forgotten to replace
any hoses, clamps, of bolts.
17. Start the bike as normal when cold, using prime and choke as
required. (Some fuel may have drained out of the float bowl when it
was rotated.)
18. Warm the bike up full and test ride it.
19. If you wish to tweak the pilot screw, it can be moved when the
engine is cool (to avoid getting burned) by using a flat screw driver
bit held by a small diameter rubber tubing. You can tweak the screw
in perhaps 1/4 to 1/3 a turn or out perhaps 1/4 to 1/3 turn.
20. I found that my Sherpa worked just fine at three turns out from
fully closed, was too lean at 2 turns out from fully closed, and too
rich at 3-1/2 turns out from fully closed.
============
Russ Miller from Kinston, NC