We are running about the same setup tyesai, I finally got my jetting just about smoothed out, but still working on it. I would like to try a 13/52 combo on the sprocket but the time I tried to mount the rear sprocket it wouldn't clear the rear chain guide, but i think it might have been do to the length of chain I had since it was for a 13/50 combo? For me I think a 13/52 would be perfect for most tracks in the woods, right now I'm still running a 13/50 and I find myself in second gear at 3/4 throttle, rarely hitting third gear unless it's a open shot down a path. And then when I do get into trouble and have to shift down a gear (from second) I have to use all kinds of body english, and energy, becuse of the violent hit that first gear is giving to me because I'm in the upper range of the RPM's in first. Man, just thinking about this makes me want to go down to the shop and buy a new chain and a 52 spocket to see if that will clear the chain guide? :ahhh: Anybody else have that problem with the guide? It must have been the chain.