I've got an 08 yfz450. I've taken out the baffle, removed airbox lid with k&n and outerwears.

Right now I've got 165 main,45 pilot,ncvq needle on the 4th clip, mixture screw 2 turns out, and I'm about 1000' above sea level. Its bogs and sputters high up in the RPMs-about 3/4 throttle. It idles fine low end power is good, decent midrange pull but just won't rev out.

Am i lean or rich?

Try moving to a 168 Main your pilot sounds fine I used to run my '04 at

Stock pipe with baffle out, airbox lid off and a uni foam filter at

168 Main, 45 Pilot, Zipty fuel screw 1.5-2 turns out (adjust accordingly) I also had done the cam mod.

So i say get a larger main 165 sounds like it is the stock main? Throw your K&n in the trash and put a uni foam filter or put the stock one back on with no lid, and you should be good to go.

Try moving to a 168 Main your pilot sounds fine I used to run my '04 at

Stock pipe with baffle out, airbox lid off and a uni foam filter at

168 Main, 45 Pilot, Zipty fuel screw 1.5-2 turns out (adjust accordingly) I also had done the cam mod.

So i say get a larger main 165 sounds like it is the stock main? Throw your K&n in the trash and put a uni foam filter or put the stock one back on with no lid, and you should be good to go.

:rofl Uni does make a great product. i concur on the main jet. :+1 try a 168, will probably make all the difference.

I'll third the UNI vote, I used to be a K&N poster child but I switched to UNI on all the race engines that I don't use an airbox on.

They were kidding abut throwing away the K&N. That is money. Save it you might need it later. These guys run unis for racing. My KN w/ power lid runs bitch'n on 06' YFZ for rev'n in the dunes.

The needle on the 4th clip is what bothers me. That a lotta of fuel. The needle adjustment works for 1/4 to 3/4 throttle. Main jets work on 3/4 to full throttle. Pilot jets work on idle to 1/4 throttle. Keep that in mind when jetting.
I would try putting the needle on the 2 or 3 clip and try that.

One more thing, remember that the engine does not react the same while standing still. You have to test while moving, its a long process but worth it !!!