I finally bit the bullet and picked up a carb synchronization tool. True to form, I stuck with the cheapest one I could find - for the uninitiated, this is a quartet of long, thin rigid plastic cylinders fixed to a backplate marked in centimeters, a reservior of mercury in which the tubes sit, and a set of flexible tubes to connect each cylinder to a carb vaccum port. Basically, it's four really long thermometers that you hook up to your engine. The suction generated by the vacuum port on the carb draws the mercury up the cylinder, and the goal is to even out the suction on each carb such that each mercury column is the same height. Apparently this is important for fuel economy, power, and idle performance.

This was a bit of a more in-depth operation than, say, changing the oil (open oil port, drain oil, close oil port, fill with new oil). To expose the carbs enough to hook all this good stuff up, you need to remove the seat (easy), and then the rear bodywork panels (a bit fiddly, but not too bad), followed by the fuel tank. Getting the tank off isn't a problem, but figuring out where to put it afterwards such that you can get to the carbs but the tank can still feed them fuel is a challenge. Suzukis also feature fuel petcocks that connect to the vacuum port on one of the carbs, and won't properly feed without that connection unless you remember to set the petcock to the PRIME position - which, naturally, I forgot until well into the operation, after I'd removed the handle from the petcock. I also stuck a box fan in front of the bike to help cool the engine, since it would be running yet stationary for some time.

Once everything's hooked up properly, one starts the engine and lets it come up to normal operating temperature. Then it's time for the actual synch procedure, which - like most maintenance I've tried my hand at - isn't hard, per se, but is a bit of a learning experience the first time through. Carbs 3 and 4 are first synched to each other, than 1 and 2, and then finally the individual pairs are synched.

They were, of course, grossly out of tune when I first started Zoë up. After about 15 minutes of examining the mercury, making a small change to one of the set-screws, and repeating, I had them at a pretty even keel across the board. I'd like to think that the engine sounded smoother when I was finished than I had before, but honestly I don't have the slightest idea if I accomplished anything. Strangely, I did find that when at idle the carbs were each drawing exactly the same, but when I throttled up to ~3500 RPM, carbs 1 and 4 looked to be drawing harder than 2 and 3. I tried adjusting 1 and 4 down so that they'd synch up at speed, but couldn't seem to get it just right, so in the end I just stuck with the instructions and dialed everything for an even idle. Hopefully that's the correct approach.

Other minor tasks today: setting the appropriate chain tension again and actually getting the right torque on the axle nut, now that I've got a torque wrench. I wanted to really go hardcore and adjust the valves, but I'm lacking feeler gauges, and I guess there's some O-rings that need to be replaced if one takes off the valve cover. All in all, given the terrible conditions in which I do my wrenching (no garage, for starters), I think this was enough for today.

Some pics:

Here's as close as I come to a garage. It's mighty cold out there, but at least it's dry. Of course, one of these days, the wind's going to blow real hard, and my garage is going to fly off into the neighbors' yard, but what can ya do?

There's Zoë with her tank all cockeyed, looking like some strange superbike. The white thing hanging from the left handlebar is the synch tool, and you can see the vacuum hoses leading from it to the engine. Also note that the rear bodywork is all removed.

More of the same, from above. See how well-organized my tools are? :)

And that, right there, is some fine, fine carb-synchronizin', my friends.