Now wont start

Saturday morn, my kz305, set choke and it started right up at home. Drove to work, about 10 miles, no problem. After work, I set the choke and tried to start. No go, just cranks and cranks and no start. I'm thinking flooded because day was warm and should not have used the choke. Had coworkers push a bit, while stifling their laughter, , popped clutched and it started right up. Rode fine going home, just a bit rough but smoothed out nicely after a mile or two. Got home let it sit a bit. Tried to start and it just cranked and cranked. What do I look for, battery? ThanksY

You don't give much for bike info, what year and model is your 305? Put it in your profile, in your user account.
Look at the spark plugs, and if it still has them the points condenser. If it cranks with the starter, and cranks well, then I don't think its a battery or charging issue. You could have a bad connection, giving low voltage to the ignition coil, or it could be a fuel level problem, being to high and causing flooding. Any fuel below the bike, or in the crankcase oil after sitting?
Have you checked your valve clearances, maybe they are to tight? Pretty easy on the 305.

1960vw wrote: Saturday morn, my kz305, set choke and it started right up at home. Drove to work, about 10 miles, no problem. After work, I set the choke and tried to start. No go, just cranks and cranks and no start. I'm thinking flooded because day was warm and should not have used the choke. Had coworkers push a bit, while stifling their laughter, , popped clutched and it started right up. Rode fine going home, just a bit rough but smoothed out nicely after a mile or two. Got home let it sit a bit. Tried to start and it just cranked and cranked. What do I look for, battery? ThanksY

Does it have a kickstarter?

Well, thanks for input. It indeed was a bad battery. Not supplying enough voltage to coils. Bought new one, old was over two years old, and runs like a champ !!!

Another bad battery causing no start, glad it was an easy fix for you. If you park it for long periods use a battery tender/ float charger.