JasH,
I have an 02 raptor with the same pipe but just the filter no pro flow kit. I haven't messed with my jetting and I need to cause I'm lean but haven't rode that much since I got my new yfz. Anyways, you should be judging your jetting at the ceramic portion of the plug. That's the white part when it's brand new. It doesn't matter what the threads look like. The ceramic should be a light tan/brown color. If it's white, it's lean and if it's black it's rich. The deceleration backfiring is more than likely your needle position being too lean. I learned a lot more than I already knew when I did my YFZ450 jetting from this site http://www.eskimo.com/~daddog/jetting about the 450, but it teaches you all you need to know about jetting and more. It's been some time so search through the document and it tells you the generics about jetting, not just the YFZ450.

 

do you mean the center part of the plug the part where the thing comes out that gets fire is that where i look

 

yep

 

thaks alot man i appreciate it