Do you have any suggestions?
You will want to make sure none of your fuel lines are clogged, for starters. Make sure fuel is getting from the tank to the frame petcock, and from the frame petcock to the carbs (carb bowls fill up when petcock is in PRI position, carb bowls fill gradually only when engine is cranked with petcock in ON or RES). After you have ensured that fuel is getting from the tank to the carbs, you need to make sure fuel is getting from the carbs to the cylinders. Make sure your jets aren't clogged and that the carb slides are functioning properly. There are a few threads on here that you can find that will provide you with information on cleaning the carbs. If the bike has been sitting a while, I would imagine there could be some residue in the carbs so cleaning them would be a good thing to do regardless of what your problem actually is.
After you've verified you're getting fuel to the cylinders, if the bike is still not starting, ensure the spark plugs are functioning. I doubt you will have to check the spark plugs, since you said you had it running before.
My bet is clogged fuel line somewhere preventing fuel from getting to the carbs.
this is new to me. how do i check for a spark?
Remove the spark plug, then re-connect the wire and ground the plug somewhere and crank the engine. You should be able to see the spark. Do make sure that there is no residual fuel on the plugs or near where you are doing this. You don't want to cause a fire.