My KDX250sr weighs 297 ready to ride, apparently a lot of the weight is in the frame so I'm really just looking for a lighter frame.Early Kawasaki perimeter frames had a rep' for being heavy, so I'm chasing the oldest one that will still take a lot of my parts.The 250sr engine has a balance shaft and autolube so they will be adding to the problem.I'll strip the bike soon and weigh everything.
Like your CR500 idea, that will have no problem hauling the weight.