Backfire

[cottam109]

I just got a 2009 YZ 250F and when I come into corners no matter what gear I am in my bike begins to backfire as I decelerate. Is this potentially harmful? And if so how can I go about fixing it?

[FORMA MOTO]

It's not a backfire unless it comes out the carb.

It's lean popping.

 

Adjust your fuel screw for cleanest highest idle

 

If that doesn't do it, it can be a number of things.

 

If you have not serviced your carb or adjusted your valves before, you might need to.

 

There are BILLIONS of posts on the subject.

 

Until you tell us your jetting, hours, mods, condition etc, there is no way to help you

[cottam109]

It is bone stock. Only around 10 hours.