Suzuki carry 660cc or 1000cc?

Generally speaking, the opposite is true. When all else is equal, a larger engine creates more power but uses more fuel in the process.

Suzuki Carry 1000 Cc

This is what I have learned about engine size vs fuel economy from my experience with cars

-A 2700lb jeepster with a 5.7L vs a 3700 lb 4runner with a 3.0L. Jeepster had power, lots and lots of power. It didn't take much trottle to go. 4runner has no power and needs to be gunned if you want to go places. Hills and stuff suck gas in it. Both could achieve 18 mpgs on the freeway.

Make sure the motor can pull your own weight, because a smaller motor might just work 2x harder to do what the bigger motor can do. Being underpowered will give poor fuel economy if you have to work the engine.