Has anyone used a liquid carb cleaner in their bike before? What are the disadvantages of using this? I'm curious to try it and know the results because I definitely won't be doing any manual carb cleaning this year

Oh the stuff made by yamaha that needs to be mixed wiht hot water - yes it usually turns aluminum grey/black.
Open and clean, and spray on cleaner works for small parts when out in the open. The other stuff does not belong near a bike. Your carbs have a shiny aluminum color ... they would not turn dull grey and give off white flour like crap when contact with water.
Cool.
Buddha.

Just run some potassium permanganate through the tank.  It'll clean it in a jiffy.   

I've used seafoam, but usually only when I'm not going to ride the bike for a while, more like a fuel stabilizer.  If your carbs are causing you trouble, nothing beats a manual cleaning.  Shouldn't take more than an hour.

Who has an hour?
This'll clean 'em in a flash:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170504754081&rvr_id=132001179385&crlp=1_263602_263622&UA=WXF%3F&GUID=c441c95612a0a47a2f301040ffeb4f18&itemid=170504754081&ff4=263602_263622

Don't even need that much.  Sell some for profit.