yfz 450 back fires

[STRAIGHTUPDAHILL]

the duratraxx flashpoint is a handy little unit

[Jasonp]

this is actually pretty simple..
Jetting works off of throttle postion. So let say you at full throttle (that would be the main jet) 5th gear and you let off the gas all the way and your slowing down. You would be on the pilot jet/fuel screw, air jet now.. "pilot circuit." Now if your backfiring out the exhaust that means you are lean on that circuit. Back the screw out a 1/4 turn or so and that will fix your problem.

[ElderGeek]

May I suggest you read this link on YFZ jetting. I used this info and mine now runs like a champ. The info applies even as you do more mods to your quad down the road. Jetting is a trial and error thing but this helps you get in the ball park then fine tune from there.

Print it out and put it in your tool box.

DadDog Jetting


How to videos at the bottom of the thread.......

More stuff here.here

[STRAIGHTUPDAHILL]

check to see if your slider is returning quickly when you let go of the throttle..it may be hesitating causing a temp rich condition on release

[give me a break]

One thing that will cause any machine to backfire is loose exhuast headers check to see if they are tight do not over tighten as you can break them right off they take about 8lbs tourqe on them i do 7

[Xtreme26181]

You guys like to shine= probly a motor full of chrome and bright colors ==
HOT HOT HOT motor..... Paint everything flat black = cools the motor more then you think