Edelbrock YFZ450 User Manual

INSTRUCTION SUPPLEMENT FOR 2004-

LATER YAMAHA YFZ450

Removing stock carburetor and cables.

1. Remove seat and gas tank. Make sure fuel
petcock is in “off” position.

2. Remove throttle cable paying close attention
to routing, as the new cable(s) will need too
be routed the same.

3. Remove stock carburetor and stock throttle
housing. Stuff a clean, dry rag into manifold
to keep debris out of motor.

IMPORTANT NOTE: This machine is equipped
with a throttle over-ride system (TORS) and a
neutral safety switch. You must unplug the
TORS

From the wiring harness located near the
steering stem top mount. The neutral safety

switch located on the clutch perch must also be
removed and unplugged. Once unplugged,
tape the two wires together that come out of th e
wiring harness.

Carburetor installation

1. Carefully trim the rubber alignment tab off of
the face of the manifold with a razor blade or
side cutters.

2. Remove the hex pipe plug from the carb cap
using a 11mm or 7/16 wrench. Do not
disc ard plug, as it will be needed later.
Install the metering adjustment tool included
in the hardware kit. Do not over-tighten as

damage may oc cur to cap.

1. Attach fuel line to carburetor and secure with
clamp.

2. Place carburetor into manifold and air boot.
Tighten clamps with carb sitting as close to
vertical as possible.

Twist Throttle Instructions

1. Install the throttle cables into the supplied
throttle housing and place onto clean
handlebar end.

2. Route throttle cables through frame as stock
cable was routed.

3. Install the pull cable into the 8:00 position
and the return cable end into the 11:00
position of the cable wheel. Secure cables
to cable bracket by replacing e nd piece and
Phillips screw. See figure 2.

NOTE: SEE FIGURE 1 TO IDENTIFY CABLES.
The bottom cable is the pull c able.

Figure1.

Figure 2.

Thumb Throttle Instructions

NOTE: Modificatio n of the stock thumb
throttle housing will be required in order to
achieve wide open throttle. Figure 3 will
show the mods.

Figure 3.

Material will need to be removed on the
outside throttle stop that limits the thumb
lever travel.

Once throttle housing has been properly
modified and thoroughly cleaned, place and
secure back onto handle bar.

3. Threa d new throttle cable into housing and
insert cable end into throttle lever.

4. Install cable into cable wheel o n carburetor
in the 8:00 position and secure cable into
lower slot on cable bracket by replacing end
piece and Phillips screw. See figure 6.

5. Adjust throttle cable to take up the slack in
the throttle . Note: When throttle cables are

properly adjusted, there should be
approx. 1/8” of free play in the throttle.

6. 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.

7. Install fuel tank an d connect fu el line to
petcock and secure with provided pinch
clamp. Do not bolt tank in place, as minor
adjustments may be necessary an d my be
easier with the tank off.

8. Turn fuel pe tcock to “on” and check for
leaks.

9. Open throttle 3-5 times to prime accelerator
pump. Do not open throttle any more than
5 times as this may flood engine!!

10. Once pump is primed, If Motor will not fire
open idle cable ½ turn and re peat starting
process.

NOTE: If flooding occurs, slowly open
throttle to wide open and hold. With
throttle still open engage starter until
engine fires.

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 #3177 and #3178 YFZ450

Carburetor Specifications

Bore Size: 40mm

Needle: K-6 @ 1 2 Clicks

Accelerator Pump Bypass: 1 3/4 turns out

Alternate Needles: K-5, K-7

Replacement Cable
Thumb #9339
Twist #9355