1.3 Ah sounds small to me also. But let's look at the math for 40 Cold Cranking Amps. (I can switch batteries between 3 of my bikes, all 14Ah delivering 35 to 40 cca.) At 40 amp draw, a 1.3Ah battery should last 1.95 minutes. If that was lead-acid, the voltage would drop significantly before the end, but a lithium or even nickel battery will provide more voltage longer (then die quickly). But if the battery can deliver 35 to 40cca, the starter actually draws far less in normal use.