[SLESTAK75]

Do you have the 20mm roller style variator mb or standard size? When you lay the pulley on the table with the shaft facing up. The lip that the spring sits in is the bottom part of the cover for the groove channels. I had to take a hammer and tap a screwdriver under the lip in order to loosen it. Then twist and pull up to remove. It's on there pretty tight to the point that I thought it wasn't removable. Once this cover is off you will see the groove channels. Just remove the three pins (they come right out) and spin that half of the pulley until the holes line up in the next groove then replace pins and cover. The cover was as difficult to replace as it was to remove. I had to tap it with the hammer to get the cover on. Be careful not to hit it hard. Then voila