best yzf 400/426 mod

6 replies to this topic
  • mlb731

Posted March 22, 2008 - 11:07 AM


just got my hands on a nice yz400f pretty cheap. I have not riden a 4 stroke since my xr80 when I was kid (converted 2-stroker). What is the single best mod for this bike? I have a 100 mile desert race next month (elv. 1200ft) and could use some solid advice on getting my bike ready.

  • Smokeslider

Posted March 22, 2008 - 11:18 AM


Hot-Cams Auto-decompression cam.....makes your life much easier.

  • BRYANS01

Posted March 22, 2008 - 11:28 AM


best thing Ive done on my 426 is the zipty fuel screw and the jd jet kit. i would think it will be the same outcome on the 400.

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  • jmckinney

Posted March 22, 2008 - 07:01 PM


I agree with BRYANS01... I have a 2000 YZ426 and the fuel screw and JD jet kit is wirth every penny...

  • 1rkcooper

Posted March 22, 2008 - 07:12 PM


At the top of the yz forum there is a sticky with common threads, have a look in there for a ton of useful information.
My vote goes to the auto decompression mod.

  • BRYANS01

Posted March 22, 2008 - 07:37 PM


I agree that the decomp cam is one of the best things you can do, but if he just got the bike these simple and inexpensive mods are well worth the money if the bike is in good shape save the cam mod for the rebuild. not trying to step on any toes just my opinion.

  • tom nolan

Posted March 22, 2008 - 08:29 PM


If your going to race in the desert, you'll need to up the gearing. I raced district 38 for years and I recomend 15 front and 44 rear. The engine has the grunt to pull those tall gears and your top speed should be just a tick over 100. Also, get a zip tie jet and a boyseen quick shot pump housing and a scotts steering stabilizer. The stock pipe works great and no need to spend all the bucks on all that afterarket crap because when your wide open the difference from stock and aftermarket is zillch. After that, your set for your first race. Good luck.

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