New 06' YZ 450F Questions

[Ricky500d]

Hey guys, Im new to the whole 4 stroke thing. I just bought a brand new 06' YZ 450F and I have a few questions. First of all, I live in San Diego (Lemon Grove area) so i know that I'm pretty close to sea level. Im in the process of breaking it in nice and easy but I notice there is a lot of backfire when I let off of the throttle in any gear. It also backfires when I just rev it up a bit. Also, while I let the bike warm up and give it a little throttle hesitates for a second. I was just wondering if all these symptoms were normal or mabe my jetting is off. Any help would be much appreciatied.

Thanks,
Ricky

 

[NE14MX]

Yes the jetting is off. Turn the fuel screw out a half turn. Look in the manual to see where it is on the carb. It's hard to get to and needs to be adjuted often per weather conditions, etc. That's why most people get an easy adjustable fuel screw.

 

[Ricky500d]

I know where it is and I was going to do that but i just wanted to here what others thought. Thanks for the help.

 

[CROGGR]

I know where it is and I was going to do that but i just wanted to here what others thought. Thanks for the help.

You need to replace the stock 42 pilot jet with a 48 and the back firing will stop and you will experience much stronger pull off the bottom with better throttle response.

 

[Ricky500d]

You need to replace the stock 42 pilot jet with a 48 and the back firing will stop and you will experience much stronger pull off the bottom with better throttle response.

The 48 pilot jet will make that big of difference even though im not in cold temperatures and I ride at sea level?

 

[CROGGR]

The 48 pilot jet will make that big of difference even though im not in cold temperatures and I ride at sea level?

YES!!!

 

[JordoMX]

SD riding

Hi Ricky
I got a new YZ450F too and really love it!
I have to be in San Diego next weekend visiting my wife's relatives.
Where is a place to ride near SD that I could sneak out to for the afternoon?

 

[YamiDude]

Yes go with the 48 pilot and I have 170 main and no backfiring and great power throughout range. Like it has been said you should get the adjustablke fuel screw as you will need to adjust it often. Only other thing that others have done is lower the needle clip but I still have mine in stock position. I ride sea level and its 60 degrees right now...may go to 45 pilot and 165 main but will see as it warms up.