My buddy just took his 05 CRF 250 out for its maiden voyage. Loves the bike; its light and fast. But, the only problem is, is for the first ride, we rode trails. This wouldn't be a big deal, except this is the first bike he's ridden in a few years, and it doesn't have a whole lot of bottom end; well, none... I'm getting him a flywheel weight, but the only problem is, is I don't know what size to get him. He wants the bike to be plenty torquey for when he rides trails, but he still wants enough top end for when he opens it up. What weight is reccommended? I was thinking either the 11 or 13, but I want other opinions first. Thanks.