jetting my 04 yfz450

[skinz350]

I bought a used 450 with a pro circut t4 slip on. the mid to top seems fine but the low end seems a little lean. Backfire when i let off the throttle and will not idle when i turn the choke off. I am running a air box lid with a pro design pro flow foam filter. Any one have any info for me before i start messing with it. Or what works good for you?
Thanks.

[yfzfelix]

I would remove the pilot jet and see if its plugged, if its not check the A/F screw, it should be 2 to 2 1/2 turns out, turn up the idle, if it still won't idle then I would go up to the next pilot size and try again, good luck with it, Steve

[skinz350]

Thanks, ill give it a shot