V-Star Carburetor Synchronization
The Yamaha V-Star vacuum ports are not so easy to get to. I've seen where some guys do a mod to extend the hoses to the toolbox area so that they can be easily accessed. One article I read, talked about removing the gas tank and air manifold to do the adjustment. I disagree with that because the complete air system should be intact when balancing, otherwise the balance won't be right when its all back together.
Actually, all that needs to be removed is the carb cover on the left side and the air cleaner unit on the right side. Both just require the removal of two allen head screws, assuming that the air cleaner can be pulled free from the rubber air duct. Mine is a little greasy and it slips in and out. If yours is snug, you may have to loosen the phillips head screw in the clamp, which is a challenge because its close to the bottom of the tank.
I took the AIS hose and port cap loose while the bike was still cold - easier to work on without getting burned. Then I put the smallest bit of silcone grease on the fittings so the hose and cap slips off pretty easy once the clamps are loose. This makes it much easier to get apart when the bike is hot.
Warm the bike up, and then put the manometer hoses on with the bike running. Start the bike while watching the manometer. (See here for
instructions on building a manometer)
If you see that the vacuum is going to suck the water out of the manometer, SHUT IT OFF! You don't want to suck water into the motor. My carbs were pretty badly out of synch, but it still didn't suck the water out. That's the advantage of having a tall manometer with lots of water in it.
Once the motor is started and idling, adjust the balance with the adjustment screw.