Yamaha YZ450FX Fuel Line Improvement Mod


ktm300dude

Hi guys, i watched what Dave Simon from ktmhusky youtube site did to the Yamaha YZ250FX fuel injector to improve low rpm response, cure the lean out issue, and stop flame outs and stalling at low rpm. Very interesting I thought, so i pulled my 16 YZ450FX apart and checked out the fuel rail and i's exactly the same. It has a sharp as 90 degree bend right on top of the injector and another sharp as 90 bend about 4 inches upstream. Not cool at all.

I have done what Dave did by getting an engineer to make a new straight shot injector top, but I had a 8mm tail with a barb made on mine so That I can use a bit of 8mm fuel injection line to push onto it and use a hose clamp to secure it. Dave made his so he still clips onto the stock 90 degree fuel fitting. I have made mine better than that to get the best possible fuel flow. I found 8mm steel fuel line on an old wreck of a car I have, a z32 300ZX with almost the perfect bends for the job. So, the injector now has a stainless steel top made with a straight up 8mm tail with a barb. The steel fuel line joins there and it goes up and then curls over like an upside down U-shape with nice curved bends (no restrictions). It then turns 90 degrees nicely and goes towards the right side of the bike. From there it curves nicely 90 degrees again and goes towards back of bike with a barb on it joining it to the stock rubber fuel injection line that goes to the tank.

There's about 40 or 50mm clearance between top of injector and the bottom of the airbox, so just enough room to do it. My steel fuel line under the airbox is almost touching, but apart from that, it's an awesome install and i love it. My YZ450FX never stalls now! I was lucky enough to find the right shape fuel line, bending it slightly to make it perfect. Apart from finding a steel line off a car, I'm not sure if an Engineer could fabricate an 8mm steel line to do the job. Because it's a fairly tight upside down U shape that goes to the injector, rubber and braided lines likely won't be suitable. Dave Simon from ktmhusky is onto something big with fixing four-stroke fuel systems. The stalling and flameouts that I experience with my YZ450FX aren't something we have to live with. It wasn't bad, but now it's just perfect in the woods. This is a cheap and awesome mod!




User Feedback




Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


  • Similar Content

    • By BDTRENT
      Selling a near new 3 gallon black IMS Tank for a 16 YZ450FX. Only has 100 miles on it.
    • By Kevdogmx
      I recently bought a 2017 yz450fxh. I'm seeing a lot of aftermarket parts listing yz450fx or yz450fxh. I did do some research and can't find anything online. I was hoping someone here might know the difference if any.  I bought the bike used with 77 hours and love the bike. I have some other questions but I will wait to see if any one here wants to talk about yz450fx's. I did not see this bike listed on the topic page, maybe to new or not too popular. Hope to find conversation about this bike. Thanks for reading, hope to hear from you. 
    • By Goof331
      Does anyone know if there is any differences between the 2 radiators? Will the yz450fx radiator bolt on a yz450f? What I am wanting to do is wire up a fan to my 2016 yz450f. I know how I am going to do it I just don’t want to use a “universal” fan kit. What I would like to do is get a 450fx radiator and the direct bolt on Trail Tech fan for that radiator to have a good clean look.
    • By Finchy637
      I just bought a Dr. D full exhaust for my bike and I've been looking around to try and find some mapping tips after I install the kit. I have the tuner. I've never mapped before but don't feel like spending the extra money to have the shop do it for me because the shops around me charge an arm and a leg. Any tips or advice? I live at 5000ft above sea level and I don't ride tracks as of right now.
    • By THE KRAN
       
      RycoMoto  REAR LIC PLATE SYSTEM (yet to order) WR HEADLIGHT ASSEMBLY  (ordered) BAJA DESIGNS REAR BRAKE HYDRALIC SWITCH* (received) ? TRIP METER SPEEDOMETER SCOTTS SUBMOUNT 1.6 RADIATOR CAP SCOTTS FRAME POST SCOTTS STEERING DAMPER*  CYCRA PROBEND CRM HAND GUARDS* G2 BAR END THREADED INSERTS GUTS RACING TALL/ MEDIUM / BLACK GRIPPER ACERBIS 2.9 GAS TANK 2015 YZ450F L & R FOOT PEG BRACKETS TMD SKID PLATE # YAMC-265   GYTR PROGRAMMER PRO CIRCUIT T6 SLIP ON* .54 / 6.3 springs  
      1.      TALLER SEAT
      2.      LOWER PEGS
      §  SWAP BRACKETS AND SPRINGS
      §  MOD PEGS
      §  WELD KICKSTAND TO NEW BRACKET
      3.      TALLER BARS (riser)
      4.      STEERING DAMPER
      5.      HANDGUARDS
      6.      FULL COVERAGE SKID PLATE
      7.      TRIP/COMPUTER (?)
      8.      SPARK ARRESTOR / TUNED MUFFLER
      9.      HEADLIGHT
      10.    TAIL LIGHT / LIC PLATE LIGHT
      11.    BRAKE LIGHT AND SWITCH
      12.    LIC PLATE BRACKET
      13.    LIGHTING ON/OFF SWITCH
      14.    LARGER FUEL TANK
      §  MICRO BATTERY
      §  HARNESS AND COMPONENT RELOCATION