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FMF Q4 Hex Spark Arrestor Slip-On Exhaust
FMF Q4 Hex Spark Arrestor Slip-On Exhaust

$341.99 - $350.99
10% Off - Save up to $39.00

Item #FMF002Z

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14 Reviews
4.9 out of 5 stars
5 Star   13 4 Star   1 3 Star   0 2 Star   0 1 Star   0
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All Reviews
Verified Purchaser
Nevada City Ca
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5
FMF q4

Great exhaust with a good sound

Perfect exhaust for this engine
Verified Purchaser
Michigan
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 4/5
Awsome product!

I just bought a 2018 rmz250 and put this Q4 S.A. on it and it sounds great. It's a bit more quiet than the stock silencer and fits and looks great.

Verified Purchaser
Oregon
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 4/5
FMF Q4

Easy to install. Make sure to save stock rubber grommets. They are required for the new install

Verified Purchaser
Durability 4/5 Ease of Installation 5/5 Performance 4/5 Power 4/5 Style 4/5

Verified Purchaser
San Jose, CA, USA
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5
Great pipe

Super easy to install. And even though its a quiet pipe. It sounds great. Much louder than stock. Power was night and day in difference

Michigan
Ease of Installation 4/5 Performance 4/5 Power 4/5 Style 3/5
Pretty good

I have 2 small annoyances with this product
1. The muffler sticks out much farther than stock and contacts my plastics. Nothing has melted yet though
2. My stock clamp is too large for this pipe. I didn't buy my bike new so it is possible that it wasn't a stock clamp but I doubt it.
Other than that, it's a nice piece, looks well made, quieter than stock.

Verified Purchaser
Raleigh, nc
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5
Perfect purchase

Motorsport are the best

FMF Q4 Hex Spark Arrestor Slip-On Exhaust
Verified Purchaser
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5

Lisbon, Portugal
Durability 4/5 Ease of Installation 4/5 Performance 5/5 Power 5/5 Style 5/5
Great Exhaust

Bought one few months ago and i couldn't be happier. Sounds great, looks nice, and definitely with more power the bike. Recommended!

FMF Q4 Hex Spark Arrestor Slip-On Exhaust
Verified Purchaser
Phelan, CA
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5
FMF Q4 installed on my 2012 CRF450R

Wanting to trail ride my CRF450R requires that I have a spark arrested pipe, which is what drove my purchase for an aftermarket exhaust. After some research I decided to go with the FMF Q4 slip-on. Reason being that it has both a spark arrestor as well as it is <96dB. Racing in AMA D37 we have to pass sound test, which this pipe accomplishes.

Overall Rating: 5 stars. I am very happy with this pipe.

Ease of Installation: 5 stars. Tools required were an 8mm, 10mm, 12mm sockets, ratchet, ratchet extension, torque wrench, and silicone sealant. You could get away without a torque wrench or silicone sealant but I always work by the book.

Style: 5 stars. This pipe fits perfect. The location of the muffler is perfect under the fender. All gaps are even and the muffler to header fitment is absolutely flush and perfect. At first I thought the pipe was damaged when I received it due to a strange crease about 5 inches back from the header, almost exactly 180° from the mid pipe bolt mount but after calling FMF to confirm before starting the installation I was informed this crease is "the factory bend to clearance the frame" and once installed I could see its purpose. When you unbox this pipe dont let this crease scare you like it did me!

Performance and Power: Both 5 stars. The pipe sounds great. Not stupid loud but still with that sweet 450 bark I like to hear. Powerwise, it is just a muffler, there may be a slight increase but it isn't life changing. I don't care what pipe you run, none will give you unbelievable HP gains but the real benefit is the reduced weight. This muffler is quite a bit lighter.

Overall, if you are looking for a muffler with a spark arrestor, a sweet exhaust note, quality construction, made in the USA, and outstanding fitment I HIGHLY recommend this one.

Sorry for the dirty fender
From the side
See 4 More Reviews
11 Questions
Answered:   7
Not Yet:   3
SethBlanchard
Q: I have a 2018 YZ250F and the stock clamp is too big for the slip on. Any help here?
2 months 15 days ago
Dalton
Q: EFI Programmer
1 year 5 months ago
If I install this with the Megabomb header, should I go and buy an EFI programmer, or reprogram the injectors? What EFI box do I need or what fuel map do I need to download?
Danno
Q: Could you please identify the difference between the "Q4 HEX" and standard "Q4"
1 year 5 months ago
whitey
Q: Is the slip on stamped FOR U.S.F.S. ?
1 year 7 months ago
fmf Q4 hex spark arrestor slip-on muffler
maxcrf250l
Q: Is the Q4 Street legal in the EU (Germany)?
2 years 4 months ago
Or maybe a hint where/how to best check? Thanks
MotoSportExpert
Expert MotoSport Staff
2 years 4 months ago
A: All products sold on MotoSport.com are for US models only. We unfortunately do not have product fitment for non-us models. Also any street legal products are designed for US emissions and laws.
Johnathon168
Q: I currently have the fmf PowerBomb header on my kx450f and it runs great with no adjustments. Would I have to change or do anything if Added this?
Over 3 years ago
MotoSportExpert
MotoSport Staff Expert
Over 3 years ago
A: Normally when installing a slip-on only minor jetting changes are needed, if any at all. If your bike is currently jetted properly you will likely not have to make any changes after installing this slip-on. I would recommend installing the exhaust and riding the bike to see how it is running then tuning your carburetor from there if necessary.
DirtBikeTimmy
Q: What to go with??
Over 3 years ago
I'm looking for a slip-on but every single exhaust talks about great power gains but there is such a price difference between them all. What are the performance differences between the Q4 and the 4.1 RCT?? In your opinion whats the best bang for your buck overall (rating all slip-ons).
MotoSportExpert
Top 1 Contributor
Over 3 years ago
A: The internal combustion engine is very simply put a basic air pump. The more air/fuel you and intake and exhaust from the motor, the more power you will make. HP gains are very subjective to gauge on any one or combination of performance parts. Things like the age of the motor, the tune of the air fuel ratio, the altitude, etc will all have an effect on PEAK HP numbers. Many performance products will not increase your PEAK HP, but rather move the HP to a different RPM range than the stock motor.

The FMF Q4 is designed for quiet forest approved riding. The 4.1 series is the newest and will give you more power than the Q4.
Hansen
Q: Does the 2014 ktm 350sxf and the 2014 husky fc350 "share" exhaust??
Over 3 years ago
MotoSportExpert
Top 1 Contributor
Over 3 years ago
A: FMF Racing list the same part number on their FMF Q4 Hex spark arrestor exhaust for both the 2014 KTM 350sxf and Husky FE350 motorcycles.
Gregrock68
Q: Compared to the stock exhaust on my 2014 kx250f, how much quieter is this unit? Using this slip on, would the bike require remapping for the effort?
Over 4 years ago
MotoSportGrantK
MotoSport Staff
Over 4 years ago
A: Your 2014 Kawasaki KX250F's stock exhaust is around 97 decibels. The FMF Q4 Hex Spark Arrestor is going to be around 94 decibels so it will be a little quieter than stock. Normally when installing a slip-on only minor fuel management changes are needed, if any at all. If your bike is currently running properly you will likely not have to make any changes after installing this slip-on. I would recommend installing the exhaust and riding the bike to see how it is running, then tune your fuel management system from there if necessary.
chestnut250
Over 4 years ago
A: It will be a bit quieter, possibly a few dB, which is a difference. Kawasaki changed the 250f exhaust from 2014 to 2015 to meet the AMA amateur mandate of 94dB. Your model ('14) is the louder of the two.

If you are going with just the slip-on no remapping will be required. If you pair it with the mega bomb or a header along those lines it will still run good but remapping would certainly help.
Hondarider
Q: Would this increase performance while keeping it close to stock db's
Over 4 years ago
MotoSportRyanT
Expert MotoSport Staff
Over 4 years ago
A: Yes, the FMF Q4 Hex would be great for increasing performance while still keeping to DB level down.
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Fitment
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# Part Numbers
Product Variant Manufacturer Part #
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 041568
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 041570
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 042341
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 043363
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044442
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 045442
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 041486
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 041479
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 042296
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 042297
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 042298
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 043325
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 043345
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 043326
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044387
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044426
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044388
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044413
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 041516
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 043338
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 045556
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 045590
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 042328
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044398
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 044435
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 045565
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 42346
FMF Q4 Hex Spark Arrestor Slip-On Exhaust 43361