FMF Fatty Pipe - 2-Stroke

FMF Fatty Pipe - 2-Stroke
FMF Fatty Pipe - 2-Stroke

$197.99 - $341.99
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  • Description
  • 81 Reviews
  • 76 Questions
  • Fitment
Description Item #FMF001X

With well over 35 years of racing experience behind it, the Fatty pipe delivers race-proven performance. The Fatty broadens and smoothes out the power curve while boosting gains throughout the entire power band, more low-end, more mid, and increased over-rev. No matter what type of riding you do, the Fatty has the benefits you're looking for.

  • More tractable power, improved throttle control.
  • Provides power gains throughout entire power band.
  • Carbon steel with a nickel-plated finish for maximum durability.
  • FMF Racing's Tru-Flo stamping process ensures a perfect fit and optimum performance.
  • Can be used with FMF or stock silencer.
  • FMF's most popular 2-stroke pipe.
  • Note: Pipe may include factory indentations for proper installation clearance.

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


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81 Reviews
4.8 out of 5 stars
5 Star   75 4 Star   11 3 Star   0 2 Star   1 1 Star   1
Reaper
Verified Purchaser
Durability   Ease of Installation   Performance   Power   Style  
Very happy

Great product, fast shipping, perfect fit

Abe95
Verified Purchaser
Durability   Ease of Installation   Performance   Power   Style  
Greatly built

I have a 97 kx250, I ordered the right pipe but did not mock up to brackets on bike, but I would highly recommend getting pipe.

simonmx33
Top 250 Contributor
Lake Wylie, SC, USA
Durability   Ease of Installation   Performance   Power   Style  
AMAZING PIPE!!

ive had this pipe for a while now, and ill tell you, this thing rocks! ive been in multiple bad crashes and not a ding on the pipe, it deffinitely freed up some power both mid and top rpm. the sound is remarkable. of course my bike is tuned and may sound different than any 125sx, but i guess itll give you a taste of how crisp it sounds, paired with the shorty, it sounds good. and ill include an attachment of the sound,

Iguanajoes
Verified Purchaser
St Johns, FL 32259, USA
Durability   Ease of Installation   Performance   Power   Style  
Second time is a charm

I was very pleased with the last fatty but had to replace when I found hairline cracks from wear over time. This one was a slightly different shape but fit after adjusting rubber mounts.

Sounds great, runs strong. I would suggest paying close attention to the bend in the pipe behind the front wheel. Keep it clean and dry to avoid premature failure.

MOTONIKO11
Panama
Durability   Ease of Installation   Performance   Power   Style  
ATC250R 1986

THE BEST IN THE MARKET,HAVE 20 YEARS AND LOOKS LIKE A NEW ONE.

mike
Verified Purchaser
Durability   Ease of Installation   Performance   Power   Style  
Its like a new bike!

Best pipe on the market with most overall power gain and great top end power. Its like a new bike!

FMF Fatty Pipe - 2-Stroke
Dteracing
Verified Purchaser
Nixa, MO 65714, USA
Durability   Ease of Installation   Performance   Power   Style  
Great pipe

Great pipe love were the power kicks in much wider range than my old gnarly

ktmrider
Durability   Ease of Installation   Performance   Power   Style  
GREAT HEADER

I recommend this header to anyone and everyone this is overall the best header around although it is kind of easy to dent but besides that I give it 5 stars

Mallett
Verified Purchaser
Pismo
Durability   Ease of Installation   Performance   Power   Style  
FMF Fatty - 2013 KTM 150XC

Took a few tries on jetting, had to lean up PJ, go to richer Needle and MJ.
Final jetting = 40 PJ, NOZH Needle and 178 MJ. Better bottom, much better mid and even better top end and over-rev.

Liked it so much on the 150XC, bought one for the 150SX as well. The 150 XC/SX is a great motor made even better, more usable and forgiving on tight technical or aggressive track riding.

2013 150XC w/ Fatty and Turbine Core
wishihadone
Durability   Ease of Installation   Performance   Power   Style  
Wish everything was this easy

The pipe was an excellent fit and went on with ease, no tweaking or adjustment needed. Engine does seem to breath a little better now. I got no real complaints about the pipe but it would be nice if it was available in black, just seems to be a shame to scratch up such a nice finish. I still need to do a little fine tuning with the carb but it seems to perform as advertised. No complaints here. I cant say anything about durability yet as it hasn't served as the impact point,,,, yet.....(fingers crossed..) but I did invest in an aluminum pipe guard to help protect the investment.

FMF Fatty Pipe - 2-Stroke
kdubb
Verified Purchaser
New York, NY, USA
Durability   Ease of Installation   Performance   Power   Style  
Great Pipe and sounds amazing.

put this pipe on my cr125 sounded great and gave it more power but i crash my bike on the side where the pipe is located and it had a bit of a dent. But this pipe shines like no other.

none
Verified Purchaser
Pennsylvania, USA
Durability   Ease of Installation   Performance   Power   Style  
Chris

I have seven bikes ,two have Gnarly pipes, one has has SST,the rest have Fattys,FMF makes the best pipes

mikesean
Top 25 Contributor
Durability   Ease of Installation   Performance   Power   Style  
Best 125 pipe out there!!!

Instant power gains and sounds amazing in the high revs, just buy it you wont regret it.

Kelly
Verified Purchaser
Brentwood, CA
Durability   Ease of Installation   Performance   Power   Style  
Fatty Pipe

Works great, looks great!

DirtSnowRider
Chico, CA, USA
Durability   Ease of Installation   Performance   Power   Style  
Great Product

Helped broaden the power band and bring the extra power I needed

Dakota2Kedik
Verified Purchaser
South Bend, IN, USA
Durability   Ease of Installation   Performance   Power   Style  
Great Bolt on HorsePower..

Great bolt on horsepower for the 2012 ktm 125 took the lowend bog away that most 125s have..Made the throttle responce alot better without rejetting or changing anything but the pipe... add the shorty silencer and WOW..WHAT A DIFFERANCE....

Great Bolt on horsePower!!!!!!!
Dirtschmobn
Top 250 Contributor
South Bay, CA
Durability   Ease of Installation   Performance   Power   Style  
Great pipe

installed on a 2000 YZ125
First off, this pipe makes the power band much broader! I am very happy with this addition. I also added the Vforce3 reed block at the same time, so I would say these are two complementary add ons. I used the jetting specs that came with the pipe and I'm loving the broadened power band and crisp throttle response. I already had an FMF turbine core silencer, so I just repacked it before installing the pipe.
The install was very easy, and the pipe comes with orings already installed. I purchased the oring kit with springs just in case, but only used the springs so my old ones could be retired.

I was however, un happy with how the pipe arrived. There were some stains on the outside (pictured) that I would hope an expensive part like this would be free of before shipping. I cleaned most of it off, but signs still remained. I noted that the durability is not high because the pipe is larger than stock, and an expansion chamber is very vulnerable anyway, and can be beat up easier. Due to the larger pipe size, I also moved the kick starter back a few teeth to maintain clearance.

one of the stains
MainJetCampbell
Top 250 Contributor Verified Purchaser
Boise, ID, USA
Durability   Ease of Installation   Performance   Power   Style  
Great Product

This pipe looks awesome sounds amazing and preforms even better!!! no qualms about this purchase from me!!! FMF Rocks!!!

FMF Fatty Pipe - 2-Stroke
SamYZ125
Durability   Ease of Installation   Performance   Power   Style  
Best two stroke pipe

I have the FMF Fatty and powercore 2 silencer on my 1999 yz 125 and it is definetly the best pipe yet. I used to have a pro circuit but it would dent so easily and eventually it got so dented i couldn't use it. I switched to the FMF Fatty and the bike had noticeably more power and sounded a lot better to. Also the fmf pipe is incredibly strong. My Fatty has one small dent and i have hit it much harder than my procircuit. FMF is definatly the best.

CORN55
lewiston id
Durability   Ease of Installation   Performance   Power   Style  
Kx 85

I bought a fmf fatty for my kids kx 85 it hung 3 inches below the frame his second ride he came up short on a double and it completely folded under the frame $224 kissed good bye. i have used fmf on all my bikes but dont recomend it on the kx 85 major flaw

fmf fatty
stock pipe
1-20 of 81

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76 Questions
Answered:   74
Not Yet:   2
Location: Tulsa
Q: Will it rust?
1 day 19 hours ago
In other words. How long will it stay shinny
Craigmack
Location: Bend, OR, USA
Q: Will this unit fit the 1991 LT250R Quadracer?
17 days ago
logan
Location: Flint, MI, USA
Q: Can i use this with a pro circuit r-304 shorty?
1 month 28 days ago
MotoSportExpert
MotoSport Staff Expert
1 month 26 days ago
A: Yes you should have no issues.
logan
Location: Flint, MI, USA
Q: Is this a left side pipe for a 2000 kx80?
1 month 28 days ago
my kx80 pipe is on the left side and in the picture it looks like its on the rights side will this pipe be on the left side when i order it.
MotoSportExpert
Expert MotoSport Staff
1 month 27 days ago
A: Yes, it would mount that same as your stock pipe. The image is a generic image supplied by the manufacturer for reference only. It may not be displaying the exact pipe for your bike. Just be sure to correctly select the Year/Make/Model of your bike before ordering so we can be sure to send you the correct pipe for your bike. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
Danb19
Location: Blackwood nj
Q: Does this come with springs?
2 months 12 days ago
MotoSportExpert
MotoSport Staff Expert
2 months 11 days ago
A: No the FMF pipes do not come with springs.
TKS100
Q: If I am currently running an SST pipe on my 02 cr125, would I have to change the jetting if I get the Fatty pipe?
3 months 28 days ago
MotoSportExpert
Expert MotoSport Staff
3 months 24 days ago
A: There is not a specific setting I could give you for jetting your bike. It would really depend on your location (altitude/temperature) and how your bike is running with the current jetting. Jetting can be very tricky, there isn't one setting that will work everywhere with every bike. If your bike is running good with your current jetting and SST pipe you will likely not need to rejet.
austin
Location: North Dakota, USA
Q: It says it will fit me 1989 yz 250 but im wondering how it fits?
4 months 15 days ago
the gnarly pipe that's on it now has a long pipe that goes up and runs along the gas tank along the bottom side of the seat and too the slip on silencer I don't see the peace that does that
MotoSportExpert
MotoSport Staff Expert
4 months 15 days ago
A: The image is a generic image supplied by the manufacturer for reference only. It may not be displaying the exact part for your bike. Just be sure to correctly select the Year/Make/Model of your bike before ordering so we can be sure to send you the correct pipe for your bike. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
jason
Location: MA
Q: Does this pipe come with a manifold that goes onto the engine?
4 months 21 days ago
if not does any one know were I could get one because mine cracked
MotoSportExpert
Expert MotoSport Staff
4 months 21 days ago
A: No the pipe would not come with the manifold. That can be found in our OEM section. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.

http://www.motosport.com/dirtbike/oem-parts
colson
Q: If I put this pipe on a stock 2015 kx100 with an fmf shorty will I need to rejet?
Over 5 months ago
MotoSportExpert
Expert MotoSport Staff
Over 5 months ago
A: There are way too many variables in jetting to give you a recommendation that works perfect. It would really depend on your location (altitude/temperature) and how your bike is running with the current jetting. Jetting can be very tricky, there isn't one setting that will work everywhere with every bike. I would recommend taking your bike to a local motorcycle dealership’s service department to have your bike properly jetted.
GoinForARipAreYaBud
Q: Will it fit with a pro circuit exhaust?
Over 6 months ago
I have a factory pro circuit silencer on my 2001 yz 125 i want to know if it will fit together
MotoSportExpert
MotoSport Staff Expert
Over 6 months ago
A: Yes the PC silencer should fit with the FMF pipe on your YZ125 with no issues.
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