On a warm summer day with a full charged fairly new extremely expensive battery, no problem cranking it over if the bike starts and runs well.
Cold weather or an engine that doesn't turn over easy as it should or add a bunch of lights and a horn, then that 4-cell might leave you stranded.
That's an awful expensive way to save a couple of pounds on a motorcycle that was built very heavy to begin with and it's hard to imagine you can't find room for a full size battery in that steel hoop frame. I'd be putting a lead acid battery in that ride and put the extra 100 bucks into tires or a chain or something useful, the tiny battery is going to buy you nothing.
