Friend of mine took his 600 to the dealer for a quick overall inspection before he went riding. He went to pickup and dealer told him to go ride and bring it back later as both power valves are stuck TIGHT and they couldn't budge them. He wants me to take a look at it. Does anyone have some tips or tricks to loosen these up so I can get them out and clean them. The dealer told him they would probably end up taking the cylinders off the motor when he brought them back. There must be something I can spray or pour on them to loosen them up. thanx. wnk.