PSA for anyone thinking about doing their own valve clearance inspection:
My 2008 is nearing 20K miles, and to be on the safe side, I decided to check the valve clearances. My local dealer quoted $480 to do this, plus the cost of replacing any shims if necessary. I said "HA! I've got some tools and a heated garage and some vacation time coming up and I need to change the plugs anyways, I'll keep my $480 and do it myself". I didn't say that out loud, but I was thinking it.
So I did it.
Of course I read all the threads in here first, and have come to the conclusion that most people in this forum who claim to have done it themselves are liars (especially the guy who said "it takes about an hour"). I also used the Suzuki technical manual, and the authors of that thing are liars too.
So, as a public service, here are my key lessons learned:
First, the manual neglects to mention the hose clamps holding the air box onto the TB. Find those and loosen them, you'll need a long 3.0mm Allen key. The manual also neglects to mention a coupler housing at the bottom front of the air box. Don't try to disconnect the hoses and wires, you will fail, just use a screwdriver to take the whole assembly off.
Second, there is not nearly enough clearance to take the valve covers off easily. For the #1 cylinder, wiring harnesses on the frame will block you, and for the #2 cylinder, a huge coolant hose runs between the frame and the valve cover with almost zero clearance. For #1, a lot of strong handed manipulation is required but it's possible to get the cover off. For #2, I found no other option but to drain the coolant and disconnect the offending hose at the top, near the coolant filler cap, and move it out of the way.
Thirdly, the valve cover gasket seats in the cover, but is also connected to the head with two half-moon shape appendages on the chain side (port side in front, starboard in back) . After you have the cover loose, you need to pull the half moon things off straight up off the head. This takes a firm hand. Be sure to do this before moving the cover too far, or risk breaking the rubber band gasket. Installation is the reverse of removal, but even more complicated because you also need to guide the gasket lobes independently of the cover, while simultaneously keeping the rest of the gasket seated as you go. It might take a few tries.
Lastly, getting the air box back on the TB is difficult, it's like trying to fit a rubber glove on someone else's hand in the dark, while their fingers are splayed out. I found that getting the front side on first, then trying to manipulate the back side worked best (or at least, was the only way that worked for me at all). Be sure the hose clamps are pointing in the right direction before you start.
From the time I started to remove the air box to the time I got it reinstalled was about 9 hours, but that includes my normal leisurely pace and several occasions where I'd pause to do something else for a few minutes when I reached a point of frustration. Knowing what I know now, beginning to end, I still see this as a 3-4 hour project.
Thankfully, all valve clearances were in spec, so I didn't need to swap any shims. I guess the peace of mind is worth the time and scraped knuckles. ?
Hopefully someone finds this helpful!