ALRIGHTY THEN. THERE SEEMS TO BE A LOT OF CONFUSION AND CONSTERNATION brought about by the use (or attempted use) of the Yamaha valve bucket holding tool for swapping shims. So here we go with a quick supplement to the original "Airhead Valve Adjustment" http://xjbikes.com/Forums/viewtopic/t=14827.html wherein by using my spare cylinder head I can show you exactly what both methods of propping open a valve entail, and the pros and cons. So, jumping out of that article: When the tool is in place and working correctly, it holds down the edge of the bucket when you rotate the cam away: (Look closely just below the cam you can see the tip of the tool engaged with the edge of the bucket.) What's going on under there is this: Which is why, in order for the tool to do its job, it needs to be as centered as possible on the cam lobe: You can see by the second pic if the tool isn't centered in relation to the bucket (and cam lobe) then it can't catch the edge of the bucket in the right spot. If you get the Tool centered on the cam lobe it will work every time. WHICH BRINGS US TO: THE "ZIP-TIE" METHOD: If you don't have access to the tool, you can use the "zip-tie" method, although I recommend using a piece of insulated solid wire (#12 or #14 will work fine.) The wire, with a small "J" bent at the end, gets shoved down the plug 'ole and hooked under the head of the open valve, into the port: ("piston's eye" view from inside combustion chamber) Then when the cam rotates away, the valve can't close all the way: Which means the shim now has enough clearance to be removed; however, a problem arises: The bucket will invariably want to lift up with the shim, as they're often quite well stuck in there: Which requires holding down the bucket while you pop the shim out: NOW WHO'S GONNA PLUCK THE SHIM OUT? You're using two hands already... This is another reason I recommend use of the tool, once three hands are involved the chance of a shim getting loose and ending up where it ought not increase exponentially. Further, I don't like probing about in my combustion chamber and risking breaking loose chunks of carbon, or disturbing the nice even carbon "cushion" each valve sits on, which is why I use the tool. If those things aren't something you feel you need to worry about, or don't have/can't get ahold of the proper tool, then at least you can see why I say to use a piece of wire rather than a Zip-Tie. It makes it much easier to decide once you understand exactly how each method works. Hope this helps, and as always, let me know if anything needs to be clarified or you'd like another picture of something I missed.