suzuki vl 125 starting problem?

Hi ,the bike usually starts first time ,no prob. runs no problem for hours.if you let it run 5 secs. 5 mins or 2 hours ,once it.s switched off, it wont start again ,thought it might be cut out switch ,not that, won,t bump start either,no spark at plugs .go back an hour later and it starts,switch it off and it wont start again cheers Mick