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The cam timing will be correct when all the dots line up on the crank pulley and the cam pulleys. You dont have to worry about the piston timing. The piston position is related to the orientation of the crank pulley. That relationship is fixed, you cant change it.
I set the piston to TDC using a long thin screwdriver through the spark plug hole. I bring the piston up on the compression stroke. At the top of the stroke I check the timing mark on the flywheel to know I am at TDC. Actually if you are slightly off, it doesnt matter cause the valves are closed for a duration. I check the valves, if they need adjusting, I then remove the belts and change out shims. I make sure to keep the piston at TDC so a valve wont drop into the combustion chamber. On the Desmoquattros, you have to remove the cams or at least pull them out slightly to slide the openinig rocker out of the way. I remove the cams completely as you have more room to work.
After valves are adjusted and checked I put on the new belts. I dont have the tool that holds the two cam pulleys on the head, so on the vertical cylinder I actually turn the engine so the crank pulley moves in the CCW direction about 5 teeth. I then rotate both head cam pulleys the same amount and then put the belts on. I then rotate the engine 5 teeth to make sure all the dots line up. Its easy to get off by one tooth, so make sure you check your cam timing carefully. Cams rotated by 5 teeth avoids dealing with the return spring that wants to rotate the cam pulleys when trying to put the belts on.
Mike
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