How can find if the CDI of my bike is working fine?

I have a 2001 Yamaha RX 135 2 stroke motor bike and have installed an aftermarket performance CDI which claimed to give me better performance and RPM rev.
But since I have installed it I seem to feel a significant loss of torque specially at lower ranges.
This is a bit of problem when I have to drive up a slope or start my bike on an inclined angle.
The CDI guys said that I might have to tune bike for rich fuel mix but am not sure how do I do it or if that would solve the problem.