Firstly kudos! I appericiate you for our interest. I think you want to follow your passion . you just try to gather deep and core knowldege about the technicality of bikes and cars. For that you need to get the right way. So, after +2 do enng. in mechanical  or automobile (any 1 as per your choice) and after that do some special or extra certification courses like:  

• Automotive Computers and Electronics Course
• Automotive Thermodynamics and Engine Design Course
• Automotive Design and Construction Course.
• Machine Elements Design Course.

So now it's upto you what you want to choose after your +2 think wisely because knwoledge will make you follow your dreams and passion too. And rememeber passion with knowledge is complete  package it will take you to greater heights.