I noticed when riding my YFZ 450 and going sorta slow in first and I gun it,it sort of sputters and sounds like its going to quit then take off. Also when your in a middle of a gear and shift to say 3rd and its in the bottom it bogs baad. I was wondering if this was a jetting problem or a problem with my timing or valves. Thanks

 

My buddies 450 did the same thing and Ive read others complaining of it. He fixed his somewhat when mods where added and it was rejetted but Ive heard many say you have to learn to kinda roll through the throttle instead of just punching it.

 

My 06 was the same way. I rejetted it. Then went for the gusto and got a RE pipe and prodesign filter. Woke it up.