FMF Expansion Chambers

 

 

 

With well over 35 years of racing experience behind it, the Fatty Gold Series 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 (unless noted)
  • Our most popular 2-stroke pipe 
  • O-Rings Included

 

The Factory Fatty is reminiscent of the “works” or cone pipe once used by Factory Teams. It shares many of the same characteristics with its’ craftsmanship and material quality. The Factory 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.

  • Lighter 20 gauge steel used for the body of the pipe.
  • 19 Gauge steel used for the header portion.
  • Includes O-rings on most models
  • Hand pounded seams for smooth flow transitions.
  • O-Rings Included

 

  The FMF Gnarly pipe focuses on increasing the lower RPM horsepower and torque to get you out of the toughest terrain. When looking to add 4-stroke tractor like torque to your 2-stroke and you need a pipe to withstand the harsh elements, this is the pipe for you. Strong and rugged, this aggressive pipe dishes out handfuls of torque and bottom to mid range pull needed for late model 200cc through 500cc machines and the rigors of the off road domain.

  • Nickel plating is an FMF trademark and has been ‘copied’ by everyone making it the most imitated expansion chamber in the world.
  • Super strong18 gauge steel construction makes it GNARLY!
  • O-Rings Included
Image Description Item Code Online Stock Price Order
FMF Expansion Chambers FMF-020015 I Fatty Pipe CR125 90-97 Header FMF Indent Only [] FMF-020015 Sold Out $439.00 Enquire
FMF Expansion Chambers FMF-020018 I Fatty Pipe CR125 98-99 Header FMF Indent Only [] FMF-020018 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020020 I Fatty Pipe CR250 97-99 Header FMF Indent Only [] FMF-020020 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020025 I Gnarly Pipe CR250 88-91 Header FMF Indent Only [] FMF-020025 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-020026 Gnarly Pipe CR500 89-01 Header FMF [] FMF-020026 Sold Out $559.00 Enquire
FMF Expansion Chambers FMF-020027 *Gnarly Pipe CR250 1992-96 Header FMF [] FMF-020027 Sold Out Was $539.00
Now $465.80 (Save 14%)
Enquire
FMF Expansion Chambers FMF-020028 I Gnarly Pipe CR250 97-99 Header FMF Indent Only [] FMF-020028 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020034 I Fatty Pipe KX250 1988 Header FMF Pipe [] FMF-020034 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020038 I Gnarly Pipe KX500 88-04 Header FMF Desert Pipe [] FMF-020038 Sold Out $549.00 Enquire
FMF Expansion Chambers FMF-020045 I Fatty Pipe KX250 1994 Header FMF Indent Only [] FMF-020045 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-020054 I Fatty Pipe KX250 97-00 Header FMF Indent Only [] FMF-020054 Sold Out Was $406.25
Now $399.00 (Save 2%)
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FMF Expansion Chambers FMF-020055 Gnarly Pipe KX500 88-04 Header FMF [] FMF-020055 Sold Out $549.00 Enquire
FMF Expansion Chambers FMF-020056 Gnarly KDX200/220 95-06 Header FMF [] FMF-020056 Sold Out $539.00 Enquire
FMF Expansion Chambers FMF-020083 I Gnarly KTM 200EXC/MXC 00-03 Header FMF Pipe Indent Only [] FMF-020083 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020092 I Fatty Pipe RM250 1989 Header FMF Indent [] FMF-020092 Sold Out $539.00 Enquire
FMF Expansion Chambers FMF-020104 I Fatty Pipe RM250 1996-98 Header FMF Indent Only [] FMF-020104 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020107 I Fatty Pipe RM125 97-00 Header FMF [] FMF-020107 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020110 I Gnarly Pipe RMX250 93-98 Header FMF [] FMF-020110 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020130 I Fatty Pipe YZ490 1990 Header FMF [] FMF-020130 Sold Out $549.00 Enquire
FMF Expansion Chambers FMF-020133 I Fatty Pipe WR200 1991-93 Header FMF [] FMF-020133 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020137 I Fatty Pipe YZ250 1993 Header FMF [] FMF-020137 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020147 I Fatty Pipe YZ125 1996-98 Header FMF [] FMF-020147 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020149 I Fatty Pipe YZ250 1997-98 Header FMF [] FMF-020149 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020156 I Gnarly Pipe YZ250 1997-98 Header FMF [] FMF-020156 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-020378 Fatty Pipe CR250 00-01 FMF Header [A] FMF-020378 Available $519.00 + Add to Cart
FMF Expansion Chambers FMF-020379 Gnarly Pipe CR250 00-01 FMF Header [] FMF-020379 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-021006 I Fatty Pipe CR250 2002 FMF Header [] FMF-021006 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-021021 I Fatty Pipe CR125 02-03 Header FMF [] FMF-021021 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-021031 I Fatty Pipe CR85 03-04 Header FMF [] FMF-021031 Sold Out $459.00 Enquire
FMF Expansion Chambers FMF-021036 I Fatty Pipe CR125 2004 Header FMF [] FMF-021036 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-021040 Fatty Pipe CR250 03-04 Header FMF [A] FMF-021040 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-021041 Gnarly Pipe CR250 03-04 Header FMF [] FMF-021041 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-021048 Fatty Pipe CR125 05-07 Header FMF [] FMF-021048 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-021052 Fatty Pipe CR250 05-07 Header FMF [A] FMF-021052 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-021053 Gnarly Pipe CR250 05-07 Header FMF [A] FMF-021053 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-022000 Fatty Pipe KX85 02-13 Header FMF [] FMF-022000 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-022006 I Fatty Pipe KX250 2001-02 Header FMF Indent Only [] FMF-022006 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-022040 I Fatty Pipe KX250 04 Header FMF Indent Only [] FMF-022040 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-022048 Fatty Pipe KX125 05-07 Header FMF [A] FMF-022048 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-022052 Fatty Pipe KX250 05-07 Header FMF [] FMF-022052 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-022053 Gnarly Pipe KX250 05-07 Header FMF [] FMF-022053 Sold Out $539.00 Enquire
FMF Expansion Chambers FMF-022055 I Factory Fatty KX250 05-07 Header FMF [] FMF-022055 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-022060 Fatty Pipe KX85 2014-18 Header FMF [A] FMF-022060 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-022062 Factory Fatty KX85 2014-18 Header FMF [] FMF-022062 Sold Out $459.00 Enquire
FMF Expansion Chambers FMF-023000 Fatty Pipe RM85 02-17 Header FMF [A] FMF-023000 Available $529.00 + Add to Cart
FMF Expansion Chambers FMF-023006 I Fatty Pipe RM250 2002 Header FMF [] FMF-023006 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-023018 I Fatty Pipe RM250 2003 Header FMF [] FMF-023018 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-023055 Fatty Pipe RM125 01-07 Header FMF [A] FMF-023055 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-023058 I Factory Fatty RM125 01-07 Header FMF [] FMF-023058 Sold Out $549.00 Enquire
FMF Expansion Chambers FMF-023059 Fatty Pipe RM250 04-08 Header FMF [] FMF-023059 Sold Out $549.00 Enquire
FMF Expansion Chambers FMF-023060 Gnarly Pipe RM250 04-08 Header FMF [] FMF-023060 Sold Out $539.00 Enquire
FMF Expansion Chambers FMF-024000 Fatty Pipe YZ85 02-18 Header FMF [A] FMF-024000 Available $479.25 + Add to Cart
FMF Expansion Chambers FMF-024039 Factory Fatty YZ85 02-18 Header FMF [A] FMF-024039 Available $479.25 + Add to Cart
FMF Expansion Chambers FMF-024041 I Fatty Pipe YZ125 00-04 Header FMF [] FMF-024041 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-024049 Fatty Pipe YZ125 05-20 YZ125X 20 Header FMF [A] FMF-024049 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-024052 Factory Fatty YZ125 05-20 YZ125X 20 FMF Header [] FMF-024052 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-024053 Fatty Pipe YZ250 1999-2020 Header FMF [] FMF-024053 Sold Out $539.00 Enquire
FMF Expansion Chambers FMF-024054 Gnarly Pipe YZ250 1999-2019 Header FMF [] FMF-024054 Sold Out $549.00 Enquire
FMF Expansion Chambers FMF-024056 Factory Fatty YZ250 99-19 Header FMF [] FMF-024056 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-024068 !Fatty Pipe YZ65 2018-20 Header FMF [A] FMF-024068 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-024069 !Factory Fatty Pipe YZ65 18-20 Header FMF [] FMF-024069 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-024072 !Fatty Pipe YZ85 2019-20 Header FMF [A] FMF-024072 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-024073 !Factory Fatty Pipe YZ85 19-20 Header FMF [] FMF-024073 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025010 Gnarly Husky 04 CR250 Header FMF [] FMF-025010 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025060 I Fatty Pipe KTM85SX 2005 Header FMF [] FMF-025060 Sold Out $459.00 Enquire
FMF Expansion Chambers FMF-025069 Fatty KTM 250/300 04-10 Header FMF [] FMF-025069 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025070 Gnarly KTM 250/300 04-10 Header FMF [A] FMF-025070 Available $549.00 + Add to Cart
FMF Expansion Chambers FMF-025073 Fatty KTM 125SX 04-10 144 SX 07-08 Header FMF [] FMF-025073 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025085 I Gnarly KTM 200 2004-05 Header FMF Pipe [] FMF-025085 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025087 Gnarly KTM 200EXC/XC 06-10 Header FMF [A] FMF-025087 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-025088 Fatty Pipe KTM85SX 06-17 Header FMF [A] FMF-025088 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-025119 Fatty KTM 125SX 12-15 125 XC 11-15 Header FMF [] FMF-025119 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025121 Factory Fatty KTM125 12-15 125 XC 11-15 Pipe Header [A] FMF-025121 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-025130 Fatty KTM 250-300 11-16 Header FMF Pipe [] FMF-025130 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025131 Gnarly KTM 250/300 11-16 Header FMF Pipe [AC] FMF-025131 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-025133 Factory Fatty KTM250/300 11-16 Header FMF TE250 14-16 [A] FMF-025133 Available $519.00 + Add to Cart
FMF Expansion Chambers FMF-025143 Gnarly KTM 200XCW 11-16 Header FMF Pipe [A] FMF-025143 Available $519.00 + Add to Cart
FMF Expansion Chambers FMF-025156 Gnarly Beta 250/300 13-18 250/300RR pipe [A] FMF-025156 Sold Out Was $499.00
Now $443.56 (Save 11%)
Enquire
FMF Expansion Chambers FMF-025157 I Factory Fatty Beta 250/300 13-19 250/300RR pipe FMF [] FMF-025157 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025172 !Gnarly GASGAS 250/300 15-16 Header FMF Pipe [] FMF-025172 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025182 Fatty KTM 125 2016-18 Header FMF Pipe 150 XCW 17-19 [] FMF-025182 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025183 Factory Fatty KTM125 2016-18 Header FMF 150 XCW 2017-19 [] FMF-025183 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025197 !Fatty Pipe KTM65 2016-19 FMF [] FMF-025197 Sold Out $479.00 Enquire
FMF Expansion Chambers FMF-025198 I Factory Fatty pipe KTM65 2016-19 FMF Indent [] FMF-025198 Sold Out $479.00 Enquire
FMF Expansion Chambers FMF-025202 Fatty KTM 250/300 2017-18 TC250/300 Header FMF Pipe [] FMF-025202 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025203 Gnarly KTM 250/300 2017-18 TC250/300 Header FMF Pipe [AC] FMF-025203 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-025204 Factory Fatty KTM250/300 17/ 18 TC250/300 header FMF [] FMF-025204 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025217 !Factory Fatty KTM65 16-18 TC65 17-18 Header FMF [A] FMF-025217 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-025218 !Gnarly Pipe GasGas 250/300 2018-19 FMF [A] FMF-025218 Available $519.00 + Add to Cart
FMF Expansion Chambers FMF-025219 !Factory Fatty GasGas 250/300 2018-19 FMF Pipe [] FMF-025219 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025221 Fatty KTM85SX/TC85 2018-19 Header FMF [A] FMF-025221 Available $519.00 + Add to Cart
FMF Expansion Chambers FMF-025222 Factory Pipe KTM85/TC85 2018- 2019 FMF [] FMF-025222 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025238 !Fatty Pipe Husky SX125 TC125 2019/20 header FMF [] FMF-025238 Sold Out $499.00 Enquire
FMF Expansion Chambers FMF-025239 Factory Fatty SX125 TC125 2019/20 header FMF [] FMF-025239 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025241 Fatty Pipe KTM 250SX 2019/20 FMF [A] FMF-025241 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-025242 !Gnarly Pipe KTM 250SX 2019/20 TC250 2019/20 FMF [A] FMF-025242 Available $499.00 + Add to Cart
FMF Expansion Chambers FMF-025243 Factory Fatty Pipe KTM 250SX TC250 2019/20 FMF [A] FMF-025243 Available $539.00 + Add to Cart
FMF Expansion Chambers FMF-025263 Fatty Pipe Beta X-Trainer 2019-20 FMF [] FMF-025263 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025269 Fatty Pipe Beta 200RR 2020 2020 FMF [] FMF-025269 Sold Out $519.00 Enquire
FMF Expansion Chambers FMF-025270 Fatty Pipe Beta 250RR/300RR 2020 FMF [] FMF-025270 Sold Out $539.00 Enquire
FMF Expansion Chambers FMF-025271 Factory Fatty Pipe Beta 250RR/ 300RR 2020 FMF [] FMF-025271 Sold Out $539.00 Enquire