Yamaha YZ450F Owner's manual

INSTRUCTION SUPPLEMENT FOR
1998-LATER YAMAHA
YZ/WR400/426/450F
Removing stock carburetor and cables
1. Remove seat and gas tank. Make
sure fuel petcock is in “off”
position.
2. Remove throttle cables paying
close attention to routing, as the
new cables will need too be routed
the same.
3. Remove stock carburetor and stock
throttle cables.
4. Unplug TPS (throttle position
sensor) and tape end off coming
from bike.
5. Remove hot start button and hose
(for externally mounted hot starts
only).
6. Stuff a dry, clean rag into the
intake manifold to keep debris from
entering engine.
NOTE: It may be easier to remove sub-
frame prior to installation.
Installing the Edelbrock Carburetor and
Throttle Cables
1. Install the provided throttle cables into
OEM throttle housing and place back
onto clean handle bar.
2. Remove the rubber carburetor
alignment tabs from the manifold using
a razor blade or sharp cutters. This
should be done with the rag left in the
manifold. Be very careful not to
damage the manifold or your hands
while doing this!!
3. Remove the hex pipe plug from the
carb cap using a 11mm or 7/16 wrench.
Do not discard plug, as it will be
needed later. Install the metering
adjustment tool included in the
hardware kit. Do not over-tighten as
damage may occur to cap.
4. Install provided fuel line onto fuel inlet
banjo and secure with pinch clamp.
5. Place Edelbrock carburetor into
manifold. Do not tighten clamp yet.
6. Remove the cable bracket end from
cable bracket using #2 phillips.
7. Install pull cable (see Figure 1) end into
the 8:00 position of the cable wheel
and the return cable into the 11:00
position. Secure cables into cable
bracket by replacing end piece and
phillips screw. See figure 2.
Figure 1.
Figure 2.
SPECIAL NOTE: The Edelbrock
Carburetor was designed to be used
without TPS (throttle position sensor).
We recommend the plug be taped off to
keep debris and water from entering.
With the TPS disconnected there is no
damage that can occur to ignition
system.
8. Place provided vinyl cap over brass
barb on cylinder and secure with small
tie-wrap. See figure 3.
Figure 3.
9. Insert aluminum plug into airboot where
hot start button was located. See
figure 4. Secure with oem pinch clamp.
Pull Cable

Figure 4.
SPECIAL NOTE: Because the Edelbrock
is less prone to flooding, we have found
the hot start button to be unnecessary. If
so desired to use one, we recommend
using the TerryCable hot start kit
#HSS0001 for 01’-later models where the
hot start is built into the stock carb.
There is a fitting on the Edelbrock carbs
for this too be hooked up. For models
equipped with the external hot start
button the stock components may also
be used with a longer piece of hose.
10. Align carburetor as close to vertical as
possible and tighten manifold clamp.
11. Adjust pull cable until wide-open
throttle is achieved. Adjust return cable
to take up the slack. Note: When
throttle cables are adjusted properly,
there should be approx. 1/8” of free
play in the throttle.
12. After throttle cables have been
adjusted the handle bars should be
rotated from full right stop to full left
stop while opening and closing throttle
to ensure smooth operation. Also
check to make sure the cables do not
catch or bind on anything, i.e., hand
guards, stabilizers.
13. Secure clamp around air boot onto
back of carburetor.
14. Install remote idle cable into threaded
tab on top of carburetor. Refer to main
instruction for remote idle cable
installation and adjustment.
15. Install fuel tank and connect fuel line to
petcock and secure with remaining
pinch clamp. Turn fuel on and check
for leaks.
16. Open throttle 3-5 times to prime
accelerator pump. Do not open
throttle any more than 5 times as this
may flood engine!!
17. Once pump is primed, get motor to TDC
and kick through without opening
throttle. If Motor will not fire with a few
kicks, open idle cable ½turn and
repeat starting process.
NOTE: If flooding occurs, slowly
open throttle to wide open and
hold. With throttle still open, hold
decompression lever and kick
motor through 5-10 times.
Release throttle and
decompression lever and
proceed with normal starting
procedure.
For any questions regarding
tuning or installation of Edelbrock
products, please call our toll free
tech line M-F 8:00am-12: 30pm,
1:30pm-5:00pm PST.
877-888-7504 ext.2.
Edelbrock #3148
YZ400/426F Carburetor
Specifications
Bore Size: 40mm
Needle: K-7 @ 12 clicks
Accelerator Pump Bypass: 1 ½
turns out.
Alternate Needles: 6-K, 8-K
Replacement Throttle Cables:
#9337