I am considering stepping up to the XR650R and was wondering if they have "roller" cams in them...? By this I mean do the followers that ride on the cam use a wheel, or are they just solid tappets as is found in the XR600R? That is one thing about the 600 that I don't like. Having had to replace all the rockers, shafts, cam, and some valves already, I would prefer to sell the bike now that those things are new, than to have to replace them again later. If the 650R has a better valve train arrangement, it's just one more good reason to make the switch.