I was wondering if anybody's else 450r engine is a little noisy idling? It almost sounds like a knocking sound but it been like that since i bought it so i just figure thats just how its suppose to sound. Also how is your all's bottom end power? I went riding for the first time yesterday(after my break in period) and while trying to do dounuts in 2nd gear,in sand,it would just start bogging down. Then trying to go into burms in second,going in a little easy and then nailing it once in it,it just kind of stumbles and spark knocks some and then finally takes off.I usually had to use first gear for just about everything under 20 mph were you have to speed up and slow down.I've got a 13t sprocket on front and am thinking about going a little bigger in back to make the bottom end feel better. I also replaced my gas today thinking the spark knock was coming from bad gas. I also seen when there ars different spark plugs to run for riding conditions,which one's do you all use?