FMF Factory 4.1C Installation

18033 S. Santa Fe Ave.
Rancho Dominguez, CA 90221-5514
PH: 310-631-4363 FX: 310-900-5699
www.fmfracing.com
[05-05 / #000634]
'03-05 Yamaha YZ/WR450F
Factory4.1C
Thank you for purchasing the FMF Factory4.1C
countless hours of R & D and testing to insure you receive the highest quality product on the market today.
All FMF's products are developed using the most current technology available for design and manufacturing.
We use only the highest quality materials for function and durability. The Factory4.1C
a carbon fiber canister with a titanium mandrel bent mid-pipe. Tru-Flo modular titanium endcaps are fitted to both
ends and we utilize advanced 3-stage sound absorption packing material.
The Factory4.1C
your existing powerband to give you an all-around power increase.
POWER!
Please read all instructions thoroughly before installation. Failure to follow all installation instructions completely will void any
FMF warranty implied or otherwise. FMF Racing will not be held responsible for problems derived from improper installation and/or improper
usage.
Before you begin installing this product, be sure you are wearing eye protection and gloves. You should have a complete
understanding of how to remove and replace your stock exhaust. Otherwise, you should have it installed by a professional mechanic. Keep all
OEM parts when removing your stock exhaust, as some parts may be necessary to install the FMF exhaust depending on your particular
application.
PARTS SUPPLIED
(1) Factory4.1 Carbon Muffler
(1) Titanium Mid-pipe
(1) 8mm x 20mm Bolt
(2) 70mm Springs
(1) Stepped Aluminum Panel Spacer
Carbon mufflers are less durable than titanium or aluminum and are more easily damaged from a crash
as well as normal riding.
packing if there is indication of packing blow out as evidenced by discoloration of muffler canister (gray
carbon weave turning brown), increased exhaust sound level or change in performance.
replace packing material if water gets into the muffler. Warranty is limited on this product.
1. Make sure the engine is completely cool prior to installation and the vehicle is in a stable position.
2. Remove the right plastic side panel to gain access to the muffler.
3. Loosen the band clamp connecting the muffler to the header.
4. Remove the OEM bolt that attaches the mid-pipe to the subframe. Keep for later use.
5. While holding the muffler, loosen and remove the OEM muffler mounting bolt.
6. Gently slide the muffler rearward to release it from the header. Spray WD-40 into the muffler-header
junction if it is difficult to remove.
7. Using contact cleaner, clean the section of the header where the mid-pipe slips over then lightly coat
with a bead of High Temp Silicone for an improved seal.
muffler is the lightest slip on muffler available and specifically engineered to broaden
TM
Check out our website at www.fmfracing.com for more information.
Damage to the muffler will result from improper maintenance.
P R E - I N S TALLATION
Installation
TM
muffler for your Yamaha YZ/WR450F. We have spent
TM
8mm Wrench
10mm Wrench
12mm Wrench
Contact Cleaner
High Temp Silicone
WD-40®
ATTENTION
R E M O V A L
OEM = Original Equipment Manufacturer
muffler is constructed of
TM
Bolt on FMF performance and FEEL THE
T O O L S R E Q U I R E D
Spring Puller Tool
Replace
Always