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FMF Factory 4.1 Slip-On Exhaust - Blue Anodized Titanium With Stainless Steel Mid Pipe

Retail: $374.99 - $424.99
$349.99 - $394.99
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Product Description

The FMF Factory 4.1 slip-on exhaust is the same exhaust that professional racers use to bring home championships around the world. FMF constructed the Factory 4.1 slip-on exhaust to offer the lightest weight slip-on on the market. The technology in this slip-on exhaust cannot be found in any other exhaust. The proprietary Chamber Core technology allows for smoother and more efficient exhaust flow to maximize the power output. Since the Factory 4.1 slip-on exhaust is meant to be used for competition, FMF made this pipe ready to take to the track straight out of the box. The FMF Factory 4.1 has been designed to allow for easy maintenance with a removable sleeve for repacking and it offers the ability to fine tune the performance of the exhaust with the addition of tuning inserts and the option of a spark arrestor to give you no boundaries.

  • The lightest system available.
  • Boosts low-mid torque and offers a broader powerband with more over-rev.
  • Patented Chamber Core for optimum performance.
  • Engineered for compactness and centralized mass for improved handling.
  • Exclusive mounting design.
  • Easily serviced for re-packing.
  • Slip-on mufflers are available with a titanium or stainless steel midpipe.
  • Customizable with performance tuning inserts and spark arrestor module.
  • Meets AMA® sound requirements on most models.

Detailed Specifications:

  • Type: Slip-On.
  • Finish: Blue anodized.

Note: For closed course competition use only. Not intended for street use.

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1-4 of 5
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This muffler is trick!
Location: Eugene, OR
5 Star Muffler From FMF
If you are looking for an exhaust, this slip on application is a great addition to your bike. I installed it on my 06 YZ450F. Would buy another one in a heart beat if need be. Installation was a breeze with the slip on, the blue anodized finish is TRICK, and the muffler is holding up really well after numerous rides. RIDER BEWARE!!!!! This is a louder pipe designed for closed course riding. If your riding area is stringent on decibel ratings, think about some of FMF's quieter mufflers such as the new Q4. The new ones look much better than the ones I saw when shopping for mufflers and believe me, they will not get you tickets that end your ride!
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Verified Purchaser Featured
Location: Orange County CA
Hits Hard!
Paired this up with the Megabomb header. Night and day difference! Hit much faster than stock and noticeable mid range increase. Used this set up on 2011 YZ450F
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Location: rathdrum idaho
i had just sold my go kart and used the money i had earned to buy this and the megabomb header...i would say that is not necessarily worth the 600 dollars only because im not a pro rider i am sust starting to race. but it dafinately helped my CRF 150R in the manner of my 2nd gear holeshot, it kickes butt now...
Overall
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Ease of Installation
Performance
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Location: nanticoke, pa
the fmf slip on is the best product i have purchased it really gave my 09 yz450f a ton of power, the blue finish looks cool, and install wasnt too bad, would recommend buying the fmf jet kit also
1-4 of 5
Total Questions (4)
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1-4 of 4
DuB25 2 months 12 days ago
With this slip on exhaust, will I be able to put my Pro Moto Billet spark arrester endcap on it or does it not fit or just literally can't be put on?
MotoSport Staff
2 months 11 days ago Location: Portland, OR, USA
The Pro Moto Billet End Cap does not fit on the FMF Factory 4.1. However, you can purchase an insert to fit with the Factory 4.1.
alpha Over 3 years ago
Recomend?
which would u recomend between stainless or aluminum for trail riding?
Expert MotoSport Staff
Over 3 years ago Location: Portland, OR
You'll actually getting both with this pipe. The mid-pipe is Stainless steel and the canister is aluminum. The differences in exhausts is: Aluminum Canister/stainless steel Aluminum canister/ Titanium Carbon Canister/stainless steel Carbon Canister/Titanium
22 days ago Location: Springfield, MO, USA
Titanium all the way its the lightest yet strong and will not rust like a steel pipe would. Could get dust rust but will wipe off easily
alpha Over 3 years ago
Stronger?
which one do u think is stronger and has more durabilty,the stainles or aluminum?
MotoSport Staff Expert
Over 3 years ago Location: Portland, OR
Steel is stronger than aluminum.
alpha Over 3 years ago
?
does this come with the mid pipe?
MotoSport Staff Expert
Over 3 years ago Location: Portland, OR
Yes the mid pipe is included on the slip-on model.
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