Yoshimura 225850S321 User manual

RESEARCH&DEVELOPMENT OF AMERICA, INC.
www.yoshimura-rd.com
5420 DANIELS STREET STE A, CHINO CA., 91710 · [phone] · [phone] · FAX [phone]
NOTE: IN THE STATE OF CALIFORNIA, IT IS ILLEGAL TO MODIFY THE EMISSION CONTROL SYSTEM, WHICH INCLUDES THE CARBURETORS OF ANY VEHICLE.
You must know how to remove and replace your stock exhaust in order to install this product
otherwise have it installed by a professional mechanic. Keep all stock parts from your existing
system as some components may be necessary to install your new Yoshimura exhaust depending
on the application. Read through all instructions before beginning installation. Exhaust system can
be extremely hot. Let motorcycle cool down before beginning installation. Always wear hand and
eye protection and take precautionary measures to avoid injury.
225850S321 (SS/SS)
Honda CRF450R/RX
Qualified Manufacturer Declared “Replacement Part”
2021 ~ 2024
Signature Series systems are:
• CARB/EPA tail-pipe emissions compliant.
• Marked with appropriate EPA noise labels.
• Independent laboratory tested for EPA new
vehicle noise compliance.
RS-12 Stainless Steel Full-System

2
Assembly Diagram
22585-106
Header
x1
225850S321-RMA
Muffler
x1
Z1024
Rubber Grommet
x1
Z1024
Rubber Grommet
x1 x1 x2
RACE-SPS-1
Medium Spring
RACE-SPX-2
Small Spring
8MMNUT
8mm Flange Nut
x4
M8X25H
8mm x 25mm
Flanged Hex Bolt
x2
ST-200
Spring Puller Tool
x1
x1
347PLUG
Muffler Wash Plug

1. Remove the right side panel.
2. Loosen muffler exhaust clamp.
3. Remove muffler tailpipe chassis mount bolt.
4. While securely supporting the stock muffler
assembly, remove muffler mount bolt and
carefully remove the stock muffler assembly.
5. Remove the header nuts and carefully remove
the stock header.
1
Note : The stock exhaust port gasket will be re-
used with the Yoshimura full-system
exhaust. Inspect and replace if
necessary.
2
Note : If having difficulty removing the stock
header, inspect stock header flange
and/or exhaust port studs to see if bent.
It may be necessary to use a soft mallet
to remove the stock header off of the
studs. After removing stock header,
inspect exhaust port stud threads for
damage and check to see if bent.
3
Note : If exhaust port studs are bent, the
Yoshimura header flange may not fit and
the bent studs must be removed from the
cylinder head prior to installing the
Yoshimura system. It is recommended to
replace using OEM studs. See
supplemental exhaust port stud removal
instructions at the end of this manual if
necessary.
Removal
1. Install 22585-106, Yoshimura header using the
stock header nuts. Do not torque at this time.
2. Install Z1024, rubber grommet into muffler
bracket and install ALS-043, aluminum spacers
to the frontside and backside of the grommet.
3. Install 225850S321-RMA, Yoshimura muffler by
sliding onto header outlet. Align tailpipe chassis
mount bracket and muffler mount bracket to
subframe and secure using the stock chassis
mount and muffler mount bolts. Do not torque at
this time.
4. Torque header nuts to factory specification.
Note: If studs were removed and using M8X25H,
8mm bolts, torque to 23 Nm (2.3 kg-m,
17 ft-lb).
5. Torque tailpipe chassis mount bolt to factory
specification.
6. Torque muffler mount bolt to factory
specification.
7. Using the ST-200, spring puller tool provided in
the kit, install RACE-SPX-2, short exhaust
springs between flange and header.
8. Install RACE-SPS-1, medium exhaust spring
between muffler tailpipe and header connection.
9. Re-install right side panel following the
opposite steps of removal.
3
CAUTION: Exhaust system can be extremely hot.
Let motorcycle cool down before
beginning installation. Always wear
hand and eye protection and take
precautionary measures to avoid
injury.
WARNING: Always properly support vehicle with
a stand and/or lift when servicing or
performing any work. Unstable
vehicles may present dangerous
conditions and may cause property
damage and/or personal injury.
NOTE: Read through all instructions before
beginning installation.
Installation

10. Before starting motorcycle, check for proper
clearance between new exhaust system and
rear suspension (i.e. tire, swingarm, brakes,
rear shock, and etc.) If any problem is found,
please carefully follow through the installation
steps again. If problem still persists, please call
Yoshimura Tech Department at [phone]
/ in CA [phone].
11. It is recommended that the muffler and tailpipe
be wiped down with rubbing alcohol to remove
oil and fingerprints. This will help prevent
tarnishing of the finish after the exhaust is
heated up.
Note: After starting motorcycle, it is normal for
new exhaust system and muffler to emit
smoke until oil residue burns off.
4
Clean and inspect machined joints when servicing
the muffler during regular intervals.
Re-apply anti-seize on joints before re-installing
exhaust system to maintain durability.
Machined Joint
Care & Maintenance
If the stock exhaust port studs are bent or
damaged, please follow removal instructions below.
This kit contains header bolts however it is highly
recommended to replace using OEM studs.
1. Using (No. 5) 8MMNUT, 8mm flange nuts
supplied in the kit, thread on nut with the flange
facing outward as shown.
2. Install second flange nut onto stud facing
inward as shown. Using two 12mm wrenches,
tighten the two flange nuts to lock them
together.
3. Using a 12mm wrench, carefully turn the flange
nut closest to the exhaust port counter
clockwise to remove the stud from the cylinder
head. Repeat steps for the other stud.
4. Proceed to installation Step 1 and install header
using (No. 4) M8X25H, 8mm flanged hex head
bolt. Thread in bolts by hand and make sure not
to cross-thread the bolts in the cylinder head.
Exhaust Port Stud Removal
Stock
Stud
5

Dear Yoshimura Customer,
Congratulations and thank you for purchasing a Yoshimura Exhaust System. Over six decades of experience in research
and development, state of the art machinery, materials and craftsmanship of the highest quality all come together in a
product of exceptional quality and performance—in other words, this is the best thing you can put on your bike.
We strive to provide you with a product perfect in fit and finish. However, if you have any problems, please give us a
call. We have found that most fitment issues can be easily resolved by a conversation with one of our knowledgeable
and friendly staff. If the issue cannot be resolved this way, our warranty evaluation program may be the answer. Please
take a moment to review our recommendations for the care of your exhaust and our warranty information.
PLEASE NOTE: If you have any doubts about your exhaust: DO NOT START THE MOTORCYCLE! ONCE AN EXHAUST HAS
BEEN USED OR MODIFIED, IT CANNOT BE RETURNED FOR CREDIT OR EXCHANGE.
EXHAUST SYSTEM MAINTENANCE
Yoshimura Exhaust Systems require very little care and maintenance; here are a few tips:
1. Use mild car/motorcycle soap to clean the exhaust system—do not use any abrasives or degreasers.
2. Clean your exhaust with metal/stainless polish every 1-2 months to retain the luster and remove dirt and grime.
(DO NOT USE POLISH ON “WORKS FINISH” SYSTEMS)
3. Avoid contaminating exhaust surfaces when hot.
4. 4.Your exhaust system will change color (blue, magenta, purple, and/or gold) due to heat; this is normal.
5. Keep all clamps, bolts and other fasteners tight as exhaust systems are susceptible to vibration damage.
6. If you ride in coastal regions or areas that use salt to control ice and snow, wipe the exhaust down after it cools to
remove any possible salt residue, which can result in rusting.
7. If you are storing your motorcycle for the season, wipe the exhaust system down with rubbing alcohol before
storage.
8. Head pipes glowing (visible in normal light) may indicate an excessively lean condition that must be corrected.
CARBON FIBER:
Carbon fiber equipped exhaust components require special attention. The following addresses wear issues directly
related to carbon fiber:
1. Keep all clamps, bolts and other fasteners tight. Carbon Fiber is very susceptible to vibration damage.
2. Keep all chemicals and solvents away from the carbon fiber, as they will damage the finish.
3. High temperatures will cause the resin in the carbon fiber to break down. Visual signs such as an amber hue in the
resin may be early signs of heat damage to carbon fiber.
4. Upon seeing amber colored resin, discontinue use. The exhaust system needs to be inspected by a representative
from Yoshimura, for repack, and/or repair. Continued use will cause component failure.
STAINLESS STEEL:
Stainless Steel is not rust proof but is less prone to rusting, staining and pitting; but it is prone to oxidation like all
metals.
WORKS FINISH:
1. Works Finish exhaust systems should never be cleaned with abrasives or polishes.
2. Yoshimura recommends using “Bar Keepers Friend” cleaner to remove minor stains.
3. Surface reconditioning services are available to remove scratches and undesirable discoloration due to extreme
heat. Contact Yoshimura Tech Department at [phone] / in CA [phone] for more information.

RE-PACKING TIPS
To maintain maximum sound and engine performance the muffler packing will need to be replaced at some time during
the muffler’s life. Yoshimura recommends repacking your muffler at least once a year.
Failure to maintain the muffler packing may cause damage to the muffler and/or void the warranty. Regularly inspect
the muffler body for discoloration, cracks, rattling, or other signs of wear caused by depleted muffler packing. If muffler
packing is determined to be depleted or worn, a Yoshimura muffler re-pack kit is highly recommended to restore the
muffler to optimum maximum performance.
Yoshimura offers a 3-5 day turn around (plus transit time) to inspect and refurbish used and damaged mufflers.
For more information on muffler repacking please visit our website at: https://www.yoshimura-rd.com/pages/repack-
and-insert-chart
***PRO TIP*** Before you install your new muffler for the first-time log the weight in your Owner’s or Service manual
along with the current hours or mileage on your vehicle. When you are performing periodic maintenance on your
vehicle (like a tire change, or an oil change) you can remove your Yoshimura muffler from the vehicle and weigh it again.
Over time, the packing material inside your muffler will burn off with use, and the muffler will need to be repacked.
When the weight loses approximately 100 grams of the original weight, you should consider getting your Yoshimura
muffler repacked. You can order repacking kit or the parts to repack the muffler from the Yoshimura website, or
your local dealer. You can also contact the Yoshimura sales office and arrange to send in your muffler for the repacking
service too.
IMPORTANT TECHNICAL NOTE
Yoshimura recommends on all race exhaust systems, that all spring joints be safety wired. Recommended wire type
304/316 stainless steel with a .032” diameter should be used.
YOSHIMURA EXHAUST LIMITED WARRANTY
All Yoshimura R&D of America, Inc., exhaust systems carry a one-year limited warranty against defects in workmanship
and/or materials.
WHO IS COVERED?
This warranty is provided to the original purchaser of the exhaust system.
WHAT VOIDS THE WARRANTY?
1. Abuse, misuse, improper installation and/or modifications
2. Custom applications
3. No proof of purchase at the time of warranty. Claimant must provide proof of purchase (original receipt or invoice)
and a warranty authorization number (RMA) obtained from Yoshimura.
4. Finishes such as plating or painted surfaces with discoloration or rust due to inclement weather conditions, exposure
to salt, exposure to chemicals, or lack of maintenance by the customer are not covered.
5. International grey-market product purchased through a dealer/distributor not authorized for your country will not
be supported by this warranty.
EXTENT OF WARRANTY:
Any defective exhaust system properly returned to Yoshimura will be repaired or replaced by Yoshimura. Yoshimura is
not responsible for any other expense incurred by the customer under the terms of this limited warranty, nor is
Yoshimura responsible for any damages either consequential, incidental, special, contingent or otherwise; or expenses
or injury arising directly or indirectly from the use of the exhaust system. Any exhaust system returned to Yoshimura
must be sent at the customers expense along with the proof of purchase and warranty authorization (RMA). Yoshimura
reserves the right to determine whether the terms of the warranty, set out above, have been properly followed. In the
event that the terms are not followed this warranty is void. Yoshimura is the sole determiner of abuse, misuse,

installation errors and modifications—should any of these be found, this warranty is void. The duration of any and all
implied warranties are limited to the duration of the express warranty. All incidental or consequential damages are
hereby excluded. The warranty gives you specific legal rights and you may have other rights, which vary from state to
state. Some states do not allow the exclusion or limitation of incidental or consequential damages or limitations on how
long an implied warranty lasts, so the above limitations and exclusions may not apply to you.
If you have a fitment or other problem, or are missing a part, please double-check this trouble shooting guide first:
1. Reference your instruction sheet and double-check all drawings and instructions
2. Make sure muffler clamps are installed correctly (refer to instructions diagram). On many models, there is a right
and wrong way to install. Also verify part numbers on headers and tail pipe.
3. Always make sure to install spring-mounted manifolds and flanges on cylinder head prior to installing headers.
4. Always take time to examine problems in detail.
5. When all else fails, call our technical support line at [phone]. The technical line is open 9:00am – 4:30pm
Monday through Friday, Pacific Time. Please have the following information handy: Year/Make/Model of
motorcycle, date of purchase, place of purchase, batch dates and part numbers (found on header and tail-pipe
components).
6. Also, feel free to ask through online e-mail at [e-mail], or fax your question/problems to (909) 591-
2198.
To obtain technical information directly from Yoshimura, call [phone].