Those carbs are not difficult to clean. Disassemble, shoot carb cleaner and air through every hole and you should be good. There are tiny holes in the top of the carburetor throat, cleaner will come out of those when you shoot it in one of the holes in the front of the carb. Those got clogged up pretty good on mine once, the cleaner really made a difference. Wear goggles, it can come back at you. If you're really careful, you can sync the carburetors "good enough" without the sync tool. If I remember correctly, back the idle out until the bottom plate closes fully. Then adjust the other two until those plates are just closed. Turn the idle up and you should be in the ballpark. You can adjust it a little further by ear and get it running pretty smooth. If you have a sync tool then use it, but if you don't and you're careful you can get away without it. They are solid motors. I bought mine new in 99' and it has seen year round use in salt ever since, with lots and lots of cruising above 5000rpm. Now I'm on at least the 3rd hour meter, and it ran a few years without one (the Honda one in the dash broke, the others went dead) and this one is reading almost 500 hours, so there must be well into the thousands of hours on it.
Here's a picture of how I got the fuel screws out of mine. Just pop the top off with a screw driver, and use a left-handed screw extractor and they come out super easy. If you don't mind cutting up the carburetors, you can probably cut a groove in them with a dremmel, but I preferred not to damage the carburetor at all. The picture shows 2 broken off heads and the fuel screws removed, one is still attached to the screw extractor. The part number on the bag is the screw I replaced them all with.
