Checking your valve clearances is so easy on the boxers - another reason to love these bikes. Changing shims is easy, too, when the clearances go past the factory specs. But for some (like me) figuring out which shim I need to bring things back to the center of the range is a bit of a dark art - along the lines of brake bleeding and suspension tuning. So I finally sat down and built a spreadsheet with the selection formulas built into it. Now all I need to do is measure my clearances and record the size of the shims currently installed. Input the data into my spreadsheet and it automagically determines whether things are in spec or not, and if not, spits out how far out they are, what size shim I need to get to correct it (along with its BMW part number), and an estimate of the clearance with the new shim. Easy. I like easy. If you'd like to use this sheet next time you are checking your valve clearances, click HERE to get your free copy of Dirty_T's Wethead Shimulator. It's a Google Sheet. If you're not a Google Drive user you can download this sheet in Excel format (as well as some other open-source spreadsheet formats). Let me know how you like it! And for you Camheads, I've got one for you, too. Click here for the Dirty_T Camhead Shimulator.