Stock tires on my YZ450 are Dunlop Sports D739 G 110/90-19 and D739 FA 80/100-21. They seem slick as hell on loose terrain trails and hard pack track conditions. I had Dunlop 755/756's on my 426 and loved them. Are there any other tires you guys have found that are better than the 755/756? Loose, Colorado rocky terain. And, will a 120 fit the YZ you think?