I was wondering if swapping the complet topend(cylinder,piston,head,cam) from a XL600R onto a XR600R would be worth it? From what I can figure out doing this swap would bring the 600 up to 628cc. The piston Dia. on the XR is 97.00mm with a 80.00mm stroke.The XL is 100.0mm bore with a shorter 75.0mm stroke. Has anyone done this swap? One other question is on cams.All the info I can find says the cams in the XR and XL are the same. But on the XR500R all the specs on the cam are the same except that the lobe(lift) on the intake is 34.023 and the exhaust is 33.976.Now the 600's lobes are...Intake 31.023 and exhaust 30.976 Wouldn't higher lift be better? Thanks for any help. Don.