Do you know how to tease the wires out of the jst plug? Kevin Grannum at rcta has a pretty good video on how to do that. Anyway, tease the wires out of each plug and swap them left for right. Plug them back in and if it still acts funny swap the motor plugs.

Post some photos of the inside of your tiger and what gearboxes and motors you're using, and I might be able to help you.