2007 Yamaha V Star blowing black smoke

It sounds like the carb jetting is plugged up so that carbs should be removed and cleaned! When you first start the bike keep it idling by having someone hold it on and at the same time light touch the front and rear exhaust pipes. The carb that is working will have a hot pipe and the one not working will be cooler or cold.

need to have the injector for that cylinder checked and the tip seal replaced

IF you are running stock pipes (not "True Duals"), the right pipe exhaust ALL from the front cylinder, and SOME of the rear, and the left pipe only blows SOME of the rear alone.

The stock rear pipe splits, some going to the left pipe by itself, and the rest going to the right pipe WITH the exhaust from the front cylinder.

Now, white smoke usually indicates moisture.
Being a (non-VRod) Harley, that eliminates the liquid coolant, because there is none.

Next up that comes to mind is condensation.
BUT, this would burn off fairly quickly.

So is the white smoke only at first, or even when warmed up?
And if warmed up, is it actually coming OUT of the pipes, or OFF the pipes (like some oil burning)?

i just average joe, but i vote broken ring...sorry pal.. i recently repaired a bike...same thing was happening...in my case, the thing just had too much oil in it , so much so that it was backing into carb...jus a thought

hard call ! compression test , but sounds like your going to get your hand dirty ! P...

never leave a bike in hard rain-water was forced into carb areas like the air jets and now its runnin rich causing incomplete burnin--need to take it off engine and dry it out-and air blower from a tank works-but if bad disasemblys in order

If you have changed the air cleaner intake in any way , or the exhaust system in any way , you probably need to put a Power Commander on the cycle. If you have a Power Commander on the already, you need to hook your motorcycle back up to your computer and try a different map for your CDI box. Fuel injected motorcycles are very precisely made. They do not have the ability to compensate for changes you make to the intake and exhaust. By adding a Power Commander, You get the ability to change the fuel injection/power curve to match the changes made to the stock set up. To fix your bike you have to either put your bike back to stock ,or add (or remap) the Power Commander. If your bike is stock and giving you these issues, take it back to the dealer and have the fuel injection system checked out.

The black smoke means it is running a rich fuel mixture. first try a new air filter element, and oil change(incase fuel has flooded the sump).