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I am in the middle of doing a valve adjustment and changing the belts on my 2012 Multistrada 1200 PP and I am confused on cam/piston position when measuring the clearances. It seems that in LT Snyder’s book he sets the lay shaft at TDC (top dead center) for the horizontal cylinder; marks the belts and removes them. Then he rotates the cams by hand so that the opening cam lobe is pointing straight up and takes the measurements.

Other instructions I have seen say that the piston needs to be at TDC to measure but the opening cam lobes are not pointing straight up or out on the horizional cylinder.

Do I follow my interpretation of LT’s book and remove the belts or go to TDC on both cylinders and rotate the engine until the opening cam lobes point to the sky??? I am sure I am making it harder than it is!!!
 

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You do both. Take the belts off. Work on one cylinder at a time with the piston at TDC (so the valve doesn't fall into the bore). Turn the cam by hand and you will feel where the max clearance spot is with your feeler gauges.
 

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You can do valves without removing the belts, but it's a lot easier with the belts off.

As Yorik says the reason you want the piston you are working on at TDC is so that if the valve slips down when the retaining half-rings are removed it doesn't fall down into the cylinder... if that happens you're taking the head off to get it out. So, if you're working on the H cylinder valves, then make sure the H cylinder is at TDC. Ditto for the V cylinder. The cylinders don't have to be in any particular spot in the rotation to do the valve measurements, it's just a precaution so you don't drop a valve.

Once the belts are off you're going to rotate the cam by hand to a spot where the cams are not contacting the rocker arms to do your valve clearance measurements. You will be able to wiggle the rocker arm by hand and feel it move.

You definitely want to make sure you put the belts back on perfectly, the valves are large, clearances are tight, and if you're off by a tooth it could mean disaster if you try to start it... think bent (or broken!) valve stem. Before you remove the belts, rotate the engine so that the timing mark on the crank pulley is lined up with the one on the engine case. Then, take a picture of the camshaft pulleys on both cylinders so you can see EXACTLY where the alignment marks (or other mark you make on the cam pulley - nail polish works great and you can make as many marks as you need) line up with features (or again, paint marks you make) on the head. When you get the new belts on make sure all of the marks look exactly the same as before.

Some people mark the old belt before they remove it, transfer the marks to the new belt, and put it on so that the marks are all in the same place. Some people count teeth between the crank and first cam pulley. However you do it, the goal is to make sure that the cams are in exactly the same position relative to the crank and to each other as they were before you started. Often the timing marks on all the pulleys won't line up perfectly, sometimes the timing mark locations make it ambiguous to determine exactly which tooth they are referring to... that's where the pictures come in super handy. I will always line up the crank timing mark, then use the pictures to make sure the cams are in the correct positions. Last time I did mine I did not take pictures and really regretted it as when putting things back together it became obvious that on at least one of the pulleys there were two positions where the timing mark was equally far off of the mark on the head...

Remember to ALWAYS rotate the engine by hand once the belts are back on to make sure there's nothing hitting before you try to fire it up. I put mine up on the rear stand and put the engine in 6th gear, then use rotate the back wheel to rotate the engine... easier and cheaper than the Ducati crank rotating tool.
 
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