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FMF Factory 4.1 RCT Slip-On Exhaust [P]

Retail: $374.99 - $599.99
$339.99 - $559.99
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FMF Factory 4.1 RCT Slip-On Exhaust [P]

Product Description

The Factory 4.1 RCT incorporates the latest in FMF Resonance Chamber Technology™ both internally and externally. It starts at the center with a new core - a patent pending shape enhances and refines the exhaust pressure wave for optimal power output while lowering the sound level. In addition, it achieves a shorter overall length that is less susceptible to crash damage and complementary to the Factory Forward Engineering - moving the muffler(s) closer to the motor to centralize mass. Visible changes to the exterior include a redesigned canister to increase internal capacity for the maximum volume of packing material. The packing itself was not overlooked - a proprietary blend formulated for superior durability and sound attenuation. The final component is a new rear endcap engineered for simple tuning adjustments incorporating a snap ring feature to secure the standard and optional inserts.

  • Massive POWER gains throughout the RPM range.
  • Quieter than stock.
  • Huge weight savings.
  • Includes midpipe.
  • Can be used with FMF header or stock.
  • New RTS (Rapid Tuning System) makes for easy sound insert changes as well as adding U.S. Forestry Service Approved Spark Arrestor.
  • #1 Exhaust in AMA Supercross Series, AMA Motocross Series, FIM Motocross of Nations and the Monster Energy Cup!.

The Factory 4.1 RCT is constructed from only aerospace-grade materials that meet FMF's exacting specifications and 100% manufactured at their Southern California factory.

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4.6 out of 5 stars
5 star   8
4 star   3
3 star 0
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1 star 0
cjlyon Location: Oklahoma
1-9 of 11
Ease of Installation
Location: Oklahoma
Beware of the weight

The posted weight on motosport is 1.3 pounds, but the acutal weight is around 5 pounds. I made the mistake of trusting the website on the weight specs.

Ease of Installation
Location: Woodland Park, CO 80863, USA
Excellent Mod

Installed on my 2013 KTM 350 xcf-w and I immediately felt the difference in throttle response. Seems to pull harder earlier. Very easy to install onto stock header. Spark arrestor was extremely easy to install also. Looks and sounds great.

Ease of Installation
Location: Laveen, AZ
FMF 4.1 RCT on 2013 KTM 450

This pipe absolutely cures the common complaint about the new 450SXF's lacking on bottom end torque. 3rd gear wheelies out of hairpin corners are common now even without a click kick. Once you take your stock muffler off, try looking through it and you'll see why the bike is so choked up. Installs in a few minutes.

Verified Purchaser
Location: Southern California
2014 KTM 500 XCW

This was the best price I could find from a reputable retailer. I went with the 2 day shipping and since the product shipped the same day I received it right on time. Fitment was simple and straight forward and it performed as expected. I may adjust the TPS just to richen it up a bit and see if it makes any more power. Sounds good too.

Ease of Installation
Location: broken arrow ok
Poor mounting hardware

Good performance and look but after a few months on the bike the mounting hardware broke. Had to have it back welded on. It also broke a piece off my subframe....

Ease of Installation
Location: perry iowa
Great buy

Bought for my 2013 kx 450 and its just hits all over now

Top 250 Contributor
I love this

i bought this for my 2012 crf250r and can tell huge increase in power this pipe is awesome

Ease of Installation
Location: Colorado
Good but could be improved

This is the new 4.1 RCT silencer and it is very nice with good power gains however the lack of different sound reducers is lame. I have an older 4.1 on my KTM and it has a couple of different reducers that let you get a 96 or 98 dB level with more power or a 94 dB level with less noise but loss of low end hit. This silencer, so far, has just one 94dB S/A /noise reducer only. It is removable and this makes for quite a gain in low end power, but it is way too loud at that point. The insert has a sparky on it and that is not needed for MX so why is it there ? I do not know. I hope FMF come out with some other sound reducers/inserts to let customers tune the power and noise output like the older mufflers.

Another great FMF product

Bought this for my 2011 KX250F. Works Great, excellent quality, bolted on in minutes. Quiet pipe yet it still makes great power. Comes with the spark arrestor and quiet insert pre-installed.

1-9 of 11
Total Questions (11)
Questions with answers:
Questions without answers:
Trent179 Location: Princeton, IN 47670, USA
1-10 of 11
Eugene 2 months ago Location: Florida, USA
What is the FMF model #, want to ensure proper fit?
Please confirm the model number for the FMF 4.1 RCT exhaust for a 2014 KTM 500 EXC. Also, is the exhaust pictured the same as the model number for the KTM?
Expert MotoSport Staff
2 months ago Location: Portland, OR, USA
As long as you correctly identify your Make/Year/Model as the ride you are shopping for we would send you the correct FMF Slip-On for your bike. The image online is a generic picture of an FMF Factory 4.1 RCT Exhaust and is for reference only really, it may not be displaying the actual slip on for your specific bike. The FMF part number for the slip on for your 2014 KTM 500EXC would be #045474.
john 4 months 1 day ago Location: CA
What is the difference between buying a slip on and a header and buying the full system.?
I have been looking at the FMF Factory 4.1 titanium RCT and was wondering if there is any difference in buying the titamium header and the titanium slip on (Factory RCT), and just buying the complete system. Could u please advise if there is a differnce in the two.
Expert MotoSport Staff
3 months 25 days ago
There really would be no difference between buying the full FMF exhaust system or buying the FMF Silp-on and Header separately. They are the same pieces but FMF sells them together or as individual pieces. That way if you have the full system and either the Muffler or Header get damaged they can be replaced without having to buy the complete exhaust system again, or if you were to just get the Slip-On Muffler you could upgrade to the FMF header later. As far as the actual headers and mufflers, they are the same whether bought individually or together.
crfdude25 4 months 6 days ago
What is the difference betweern this and the TI powercore. Which will give off a deeper sound?
Expert MotoSport Staff
3 months 24 days ago Location: Portland, OR, USA
The Factory 4.1 RCT is going to be a more performance race oriented system. Although it is made to be quieter than stock, it would more than likely still have the deeper sound you are looking for. If you don't want it to be quieter, It has a removable quiet core so that you can tune the sound to your preference. There is a spark arrestor sold separately for the Factory 4.1 as well. The Powercore is a more basic system, made to be more affordable, but will still give you great performance and sound. It also comes with a removable spark arrestor and there is a 96Db sound insert that is sold separately for it. Either way you go, FMF Exhausts always have a great sound to them compared to a stock system and you'll get great performance from either System.
CRF250X 4 months 25 days ago Location: Co
Can you put this exsoust on a 2012 CRF 250X header?
MotoSport Staff
4 months 25 days ago
Unfortunately FMF does not offer the 4.1 RCT exhaust for the CRF250X model. The FMF 4.1 slip on is a great exhaust and will fit with your stock OEM head pipe.
Jordan Over 5 months ago
Is this product returnable after it has been installed?
I have a 2012 yz250f and need a quieter exhaust. I have been debating between this exhaust and the fmf q4. I want to try this exhaust out first and if it is still too loud i want to be able to return it and get the fmf q4
MotoSport Staff
Over 5 months ago
Unfortunately no, the exhaust has to be new, unused and in it's original condition.
Steve Over 6 months ago Location: 19A Russell Avenue, Wahroonga NSW 2076, Australia
Why in the pictures, the muffler has a mid pipe on it, when KTM don't have a mid pipe..?
MotoSport Staff
Over 5 months ago Location: Portland, OR, USA
The photos are for reference only and may not depict the actual exhaust specific to your bike.
ignacio01guzman Over 6 months ago Location: Chile
I served for a ktm exc 250f?
Let me know if this helps me exhaust my ktm exc 250f 2012, and I want to know if the performance of the bike would be much better than the factory exhaust brings.
MotoSport Staff
Over 6 months ago Location: Portland, OR, USA
This exhaust will help with the power delivery on your 2012 KTM 250 EXC-F. It will be less restrictive than the stock exhaust system to help increase power across the RPM range and it will also weigh less than the stock exhaust to help decrease the weight of the bike. This can be used with stock head pipe or also with the FMF head pipes for an even larger increase in horsepower.
Top 1000 Contributor
Trent179 Over 6 months ago Location: Princeton, IN 47670, USA
Tuneable endcap?
Thinking about buying this. Just curious about the tuneable endcap and spark arrestor. I race MX only and really do not need the spark arrestor. Does this come with different baffles to tune the muffler? My 13 kx450 barks loud and mean... I don't really want this to make my bike quiet. lol
MotoSport Staff
Over 6 months ago Location: Portland, OR, USA
This does include the 94 dB insert which can be removed if you like. Although this does meet the AMA sound requirement with the insert installed and it will be quieter than stock, it will not make the bike "quiet".
Nathan Over 7 months ago Location: Jefferson, GA, USA
How can i tone down the hit of my 2013 KTM 450 sx?
I recently purchased a 2013 KTM 450 sx. It is my first fuel injected bike and i have been out of riding for a while. Honestly the bike hits to hard from low to mid range, actually i feel like it skips mid range. Is there a exhaust or any other way to tone this down and make it more manageable for a weekend practice rider? Also if a slip on would help, would i need to remap with just a slip on?
MotoSport Staff
Over 7 months ago Location: Portland, OR, USA
An exhaust can help broaden the powerband. For the most effective change in power and to smooth the bike out, i would look into installing a a flywheel weight. These are a great way to mellow the power out and provide a more tractable powerband. If you give us a call we can assist with getting you the correct flywheel weight for your 2013 KTM450SXf. In addition to providing a better change in power, it is a much cheaper option also.
Ripper Over 8 months ago Location: NY, USA
Does this replace the existing two muffler set up on the 2013 CRF450r?
MotoSport Staff
Over 8 months ago Location: Portland, OR, USA
Yes, this would eliminate the dual mufflers, and convert it to single muffler on the 2013 CRF450R.
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